OO High Speed Railway Lot No.O-1 Roadbed Construction PJ Specification - Tunnelling Works OO고속철도 제O-1공구 노반신설 건설공사 공사시방서 - 터널공
1997. 05
- Contents -
1. General 2. Construction survey 3. Rock classification and application of standard section 4. Excavation and mucking 5. Support 6. Steel form work 7. Concrete lining 8. Backfill insert 9. Waterproof and drainage 10. Waterproofing for the open cut type of tunnel 11. Entrance 12. Monitoring 13. Safety and sanitation 14. Chemical grouting 15. Grouting for tunnel reinforcement (Special chemical grouting by polymer urethane) 16. Temporary electric work
제 공 처 국토교통부 출 처 Korea High Speed Rail Construction Authority 1. General
1.1 Application
(1) This Specification shows the general standards for tunneling work to be executed by NATM for Seoul-Pusan High speed Railway Construction section. (2) This specification is applicable to construction management and monitoring for NATM. (3) For aspects which are not specified in this specification, the Standard Specification by OHRC and the Standard Specification for Tunnel Construction by Ministry of Construction and Transportation shall be applied.
1.2 Work plan
(1) The Contractor shall make a work implementation plan and a work procedure of the specifications according to b, para 6, Chapt. 1 and d, para 3, Chapt 8 of the specifications and proceed to work after the Supervisor's approval. (2) Construction scope and duration and local features and the foundation condition shall be considered in making a work execution plan, and environmental pollution and traffic problem shall be minimized. (3) Cycle time for excavation and auxiliary construction method shall be reviewed in making the work plan. All the procedure shall be executed by teams, and the interrelated work shall be effected immediately between excavation team and the auxiliary construction team. (4) Nozzle men for shotcreting shall be skilled and approved by the Supervisor. (5) In excavation tunnel the Contractor shall check the condition of ground water and original subbase condition more than once a day, and keep a record for such check, and notify the owner's representative.
- 1 - (6) During the tunnel construction, the Contractor shall make and keep the tunnel construction record, such timbering works as rockbolt and shotconcrete(tunnel development) and report it to the Supervisor every week, however from time to time if necessary. Monthly report shall be made and submitted to the Supervisor.
1.3 Investigation during construction
(1) The Contractor shall check any changes in the site conditions and environment during the construction work. (2) The check lists during the construction shall include the following. (2.1) Geological conditions of the facing : rock quality, joint and ground water level. (2.2) Behavior and condition of the foundation and timbering, and stress. (2.3) Surface settlement and behavior of neighboring facilities. (2.4) Self-supportability and surrounding condition of the tunnel. (2.5) Pilot horizontal geologic survey inside tunnel. Aspect not explored during the subbase survey in the designing stage shall be executed in tunnel construction stage (2.5.1) When significant changes in the bed exist. (2.5.2) When the thickness of covering rock is thin. (2.5.3) The area where underground excavation is impossible due to passing section of obstacles. (2.5.4) When the water permeation condition needs to be checked in the horizontal direction of the subbase.
1.4 Change to construction method
(1) When the Contractor considers that the investigation results in design stage are significantly different then the site investigation, and that the original work procedure in not suitable for the site condition, the Contractor shall take temporary measures for safety and change work procedure after reviewing in full detail of rock exploration and measurement values particularly for NATM work.
- 2 - (2) The Contractor shall prepare request for change and obtain approval from. the Supervisor before changing work procedure.
- 3 - 2. Construction survey
2.1 Survey list
The Contractor shall check the central and the longitudinal lines of the tunnel by surveying with higher accuracy not only before the construction but also during the construction to confirm correct alignment from time to time.
2.2 Alignment surrey
(1) The survey of alignment shall be executed to confirm that the tunnel is constructed true to horizontal and vertical alignment as designed. (2) To prevent the accumulation of deviation occurring in each excavation, the alignment inspection shall be executed. (3) The alignment confirmation shall be executed by qualified survey engineer, in presence of the Supervisor.
2.3 The control point of outside tunnel
(1) The control point shall be installed in order to make the construction control at outside of the tunnel and interrelation defined with precision between those points. (2) The control point should be installed at place where it is not subject to damage, movement and shall be protected. (3) Installation of control point should be made with precision as required, using proper survey method depending upon the length of tunnel, condition of terrain configuration.
2.4 Tunnel survey
- 4 - (1) The tunnel station shall be measured with required precision, and shall be installed without subjecting it to any damage or movement during the construction. (2) The distance of station shall be decided considering the alignment, the size of section, and grade. (3) As the excavation proceeds, the survey of tunnel station shall be executed by inspection surveying every month from the control point of outside tunnel. (4) The curved section shall be constructed by center line of structure after surveying track and structure center.
2.5 Survey of inner section and measurement of outbreak quantity
(1) For the survey of shaft section, the measuring distance shall be decided for every 5.0m upon the Supervisor's instruction considering the field condition. (2) For measuring the inner section, laser automatic surveying instrument shall be used, and after the accurate measurement of outbreak quantity, the drawing derived from the data should be submitted to the Supervisor.
- 5 - 3. Rock classification and application of standard section
3.1 Rock classification
(1) The data of domestic and foreign should be reviewed for the rock classification, and applied Rational Classification shall be made in consultation with expert geologist (2) Classification of rock shall be decided considering the rock-quality condition, ground water condition and joint. (3) Rock mass rating system (RMR) used on the field is as follows. (3.1) Standard of classification & Point
- 6 - (3.2) Grade calibration chart in accordance with joint
- 7 - (3.3) Rock classification by grade of RMR
(3.4) Meaning of rock grade
(3.5) Effective joint slope of uncontinuous surface for excavation direction
- 8 - (4) The classification standard of badrock shall equally apply to whole procedure (design, construction, measurement), which cannot be adjusted without particular reason. (5) The classification standard shall be approved by the Supervisor, reflecting detailed opinion of an expert.
3.2 Application
(1) An excavation pattern shall be decided in accordance with the classification standard. (2) The Contractor shall execute face mapping conforming to the proposed standard and submit to the Supervisor for an approval. (3) The Supervisor, when the excavation pattern is changed, shall instruct to proceed construction, and consider it in later design change.
- 9 - 4. Excavation and mucking
4.1 General
(1) Excavation shall be executed in such a way that the badrock is not slackened as far as possible, and collapse in crown or mine shall be prevented. (2) Outbreak should be minimized by using smooth blasting method. (3) The excavation procedure and sequence in construction shall be checked considering topography, geological condition, water leakage, shape of sectional area and air. An optimum method shall be chosen and approved. (4) Lower part excavation shall be made in such way that it will not affect shotcrete layer and timbering already completed. (5) The construction Contractor shall make general measurement as soon as excavation starts. (6) The center line of excavation shall not be deviated over 5cm from the marked location in design. (7) The construction Contractor shall record the excavation work and submit a copy of the excavation peformed during the preceding date. (8) Drainage, lighting and ventilating in facing shall be managed carefully.
4.2 Extent & pattern of excavation
(1) Scale and length of excavation shall be considered with having regard to safety, constructability and economics depending upon bedrock condition. (2) For scale or bench length, cut area shall be fixed according to vibration regulation standard with considerations for bedrock condition and surrounding.
4.3 Outbreak
- 10 - The construction Contractor shall minimize outbreaks and the excessive outbrokens shall be reinforced with shotcrete and rock bolt at the Contractor's cost. Except outbreaks are caused by geological, unforeseen reasons.
4.4 Blasting excavation
4.4.1 Scheme
(1) Proposed blasting pattern shall be based on the result of boring and computation of theoretical equation. In site blasting, test blasting shall be made monthly as planned and the pattern shall be arranged accordingly. (2) A blasting scheme shall be established after verifying bedrock condition considering one time blasting length, and equipments. For the blasting method, arrangement of boring, kind/amount of powder and type of percussion shall be included in the scheme. (3) Original ground shall not be slackened by checking amount of powder according to joint and the type of soil. (4) Blasting shall be made in compliance with relevant laws and regulations.
4.4.2 Trial blasting
(1) Vibration recorder shall be installed in a place where civil complaints is expected near the seismic center to measure the actual vibration. (2) Noise shall be measured also in trial blasting. (3) The adequacy of result shall be generally evaluated whether allowable vibration value is exceeded or not comprehensively evaluating extent of outbreak, muck flying distance and size etc and conduct trial blasting. (4) Trial blasting shall be made in the following case. (4.1) Regular test blasting more than once in a month. (4.2) Adjustment of blasting pattern is required due to ground condition. (4.3) When tolerable vibration range needs to be changed.
- 11 - 4.4.3 Excavation
(1) Excavation shall be executed according to location, direction and depth as designed. (2) Attention for abnormal spring water, leakage of gas and change of geological condition shall be paid. (3) Unexploded powder shall be checked and extra holes shall not be blasted. (4) Considering decoupling exponent, gap between holes shall be regularly fixed. and bit shall be grinded with bit grinder. (5) Slime in hole, shall be totally removed using blow pipe when charging powder. (6) Mechanic excavation shall be used in principle, but in event that manual boring is inevitable due to scale of excavation, shape of cut area, ground condition etc. a well trained labor shall be employed.
4.4.4 Charging powder
(1) Charging shall be safely executed according to the blasting scheme. (2) An electric percussion shall be checked for power leakage, existence of electrostatic and its size etc for safety. (3) A blasting fuse in non-electric percussion shall be long enough for safety. (4) Handover or transport of powder or percussion shall be managed by qualified expert and daily required amount shall be handed over. (5) Transport of powder on blasting site, shall be conformed with designated method and executed by an assigned staff. (6) Charging in lower part of mine in which ground water remains nonexplosion is doubted because of impact pressure transmitted to water, therefore it is recommended that same percussion adjacent or close boring be used.
4.4.5 Blasting
(1) Blasting shall be controlled by authorized man who is qualified by law and shall ignite after checking evacuation of all workers. (2) Sufficient protections for timbering and lining shall be done prior to blasting. (3) No one can be allowed to approach to the blasting spot until after due time is
- 12 - elapsed. (4) Remaining powder in unexploded hole must be checked for proper action. (5) Vibration automatic recorder shall be used for speed of vibration.
4.4.6 Prevention of falling stones and collapse.
(1) In event that a fault layer exists near tunnel, an intensive care shall be needed, because ground water could collapse fault generating unbalanced soil pressure and amount of powder shall be reduced. (2) Insert supporting method shall be checked for the fault fractured zone against falling stone. (3) When a large cave-in causing excessive outbreak or accident is doubted, the Contractor shall obtain an approval for safe countermeasure and a work plan from the Supervisor. (4) If the excessive excavation such as cave-in happens during construction works, the Contractor should take an emergency measure with proper materials for the vacant part, and then fill it through backfilling works. (5) In case of backfilling injection, such materials should be used as to prevent the void, and secure the stability of tunnel.
4.4.7 Removing separated stones
Thorough inspection shall be made for the excavation surface after blasting, and remove carefully separated stones that could fall down. The Contractor should inspect analyze, and check crack of lining, and the other unstable factors for the excavated and supported parts.
4.4.8 Controlling blasting effect
(1) A blasting should be done not to damage the constructed structure, and the velocity of vibration should not exceed the standard value. (2) The Contractor should give a test blasting before starting excavation works for the type of rocks, and should take measures to reduce the vibration velocity within the
- 13 - allowable limits if the surveying results of test blasting exceeds allowable vibration velocity. (3) The Contractor should deal with a civil complaint when blasting. The vibration and noise should not damage the existing structure, and the Contractor should resolve cases of various civil petition caused as a result of excessive gunpowder use. (4) The allowable value of blasting vibration at the position of protecting facilities is as follows under the standard of particle velocity. Exception may be made in suburbs.
4.5 Mechanical excavation
4.5.1 Selection of excavation equipment
(1) Excavation equipments should be selected to take into account of the geological features of tunnel, section type, and length. The Contractor should submit the details of following items to The Supervisor. (1.1) The capacity of tunnel excavation suitable for tunnel route and grade. (1.2) The capacity of excavation with the specified aperture or changed aperture. (1.3) The alignment to install immediately rock bolt and steel beam at the back side of cutter head. (1.4) The device to prevent electric leakage for the electric system. (1.5) The controller of dust. (2) The Contractor should receive explanation in writing from the manufacturer of machinery as to assembling the device to operate or dismantling, the machinery according to the standard of manufacturer, and if delicately deviated, such degree of deviation is proper for the standard of manufacturer, having any effect on the
- 14 - operation of machiner.
4.5.2 Excavation
(1) The equipments for tunnel excavation should be decided to take into account of the type of cutter suitable for the geological condition, the rotation number of bit, and a driving force. (2) Equipment excavation should be conformed to excavation pattern, and The Contractor should take special care to operate the equipment endeavoring to reduce the excessive excavation. (3) The Contractor taking into account of the condition of geological feature, the weather, and construction period as given before tunnel excavation works, should prepare work program and committment plan for equipments, facilities for excavation, and submit it to the Supervisor, for approval. (4) The Contractor should make proper drainage, ventilation, and lighting taking into account of construction method and the continuity of tunnel excavation, strut, and concrete lining and should perform tunnel construction works efficiently and safely. (5) Even though construction method actually applied by the Contractor is different from original construction method and that of the approved by the Supervisor, the Contractor shall not be reimbursed for such change of work. (6) The tunnel excavation should be implemented according to TBM construction method and blasting construction method, and the Contractor should submit the details of construction method as required by this specification to the Supervisor at least 30 days before starting tunnel excavation works. (7) The Supervisor should check on the completed , surface of excavation before strut installation. (8) All the excavation works of tunnel should be done according to the line, slope, and dimension as shown on drawing. (9) The design excavation line marked on the drawing is outer limit be paid for excavation works, and except steel material strut and rock bolt is the line that which excavation material, the lumber, and other strut should not remain. Excavation pay line is the outer one to be paid for mucking, and the line to be
- 15 - paid for this line, regardless of whether actual excavation line falls inside or outside. (10) For the part that design excavation line or excavation pay line is not marked on the drawing, excavation works should be completely done to the line as required on the drawing or by the Supervisor, this line is considered as excavation pay line, where any materials, lumber, and strut except steel material strut-and rock bolt should not remain. The pay survey for excavation works should be within excavation pay line regardless of actual excavation works. but in case of unexpected falling-rocks, the Contractor should obtain the approval from the Supervisor, and may separately estimate the strut construction method and construction cost. (11) The Contractor should take special care in order that excavation works might not be done beyond excavation pay line. (12) The Contractor may change the minimum excavation line to the line resulting from the increase in concrete thickness according to the type of materials to be excavated upon approval by the Supervisor. The Contractor shall not be paid additional except for quantity increase caused by new line change in excavation pay line. (13) It is not allowable that the blasting does damage construction works, and the Contractor should restore the damaged part of construction, the damaged strut, and deviation of strut caused by the Contractor's to the extent that the Supervisor is satisfied. (14) Shortly after a blasting and before concrete placing, the Contractor should thoroughly remove the remaining rocks from excavation pay line so that stone will not fall down during the final cleaning works over entire contract period. (15) All the materials projected into the minimum excavation pay line should be removed as a part of the works as set forth in this chapter by the Contractor. Materials projected into this minimum excavation pay line should be frequently removed during construction works, and if placing concrete onto the excavated rocks the Contractor should remove or clean all the projected materials in the minimum excavation line before concrete placing
- 16 - (16) The survey for payment of excavating tunnel should be made according to the excavation pay line as directed in this chapter. (17) During tunnel works the Contractor should accurately survey with the approval of the Supervisor, and maintain the dimension and slope as indicated on the drawing. (18) Tunnel excavation by a blasting and TBM construction method should be carefully done in order that the materials outside of excavation pay line might not be slackened or destroyed. Excavation beyond the pay line should be filled with concrete at the expense of the Contractor. (19) The tunnel pattern for each section in the tunnel is estimated according to the geological data during designing works, and the Contractor should obtain approval from the Supervisor and decide tunnel pattern according to the results of the inner deviation of tunnel upon the actual survey during construction works. As tunnel pattern of the design is the standard typical one, the Contractor should acquire the approval from the Supervisor and change tunnel pattern if the site condition during construction works turns out to have specific geological features or change of excavation pattern is needed.
4.6 Mucking
(1) General : The schedule of mucking should be made to take into account of the size of section, grade, excavation method, and the condition of muck, and the Contractor should obtain prior approval from the Supervisor. (2) Mucking Equipments : Combination of mucking equipments should take into account of the capacity of each mucking equipments and decide equipments in order to do efficient works. (3) The loading works of muck (3.1) For the loading works of muck, the Contractor should take special care in order that the surrounding strut and facilities might not be damaged. (3.2) For the loading works of muck, the Contractor should take special care in order that the muck might not fall down and are not loaded excessively.
- 17 - 4.7 Transportation in the tunnel
(1) General : Transportation in the tunnel should be made taking into account safety and efficiency. (2) The condition of roadway : In case of applying tire method, the Contractor should repair the roadway to take into account of drainage in order that the favorable condition of roadway should be always maintained. (3) In case of transporting track : In case of track transportation in the tunnel, the Contractor should frequently do repair works in order that derailment might not happen. (4) The Contractor should take special care in order to prevent exhaust gas by transportation vehicles and take measures for ventilation during construction works.
- 18 - 5. Support
5.1 General
(1) Support means shotcrete, rock bolt and steel rib of which use shall be combined one another during construction as needed. (2) Generally construction sequence of support should be followed as designed, but during the construction, it can be properly adjusted depending upon behavior of original soil condition. (3) During the construction, abnormal support shall be reinforced immediately, as required. (4) Construction Contractor shall store extra material for reinforcement.
5.2 Fore poling
(1) Fore poling is temporary support material to be installed at 60° on left and right side from tunnel crown center for safety of excavated crown section, and to insure the soil protection ahead of facing and to prevent soil slackness. (2) Size and installing range (2.1) Size and installing range of fore poling shall be based on design drawing but if any change exists between rock condition and design condition, it can be increased or decreased upon approval of the Supervisor. (2.2) Installation interval of transverse direction of fore poling shall be based on 50cm, but when soil condition are different, trial installation may be made and installed within 40cm~80cm in accordance with test results. (3) Installation method (3.1) To avoid the overbreakage, installing angle should be less than 15°. (3.2) To install with the 2 point support, temporary support and soil base shall be used.
- 19 - (3.3) Fore poling shall be installed at every each gallery for natural overlapping. (3.4) Filling for drilling hole, materials should be approved by the Supervisor. (4) Installing time and sequences. (4.1) Installing time : It shall be installed after completion of primary shotcrete and sealing at fore poling install section. (4.2) Install sequences (4.2.1) Install wire mesh (after completion of excavation when fore poling already being made) (4.2.2) Install supports (4.2.3) placing primary shotcrete at side wall (which was not installed with the fore poling) (4.2.4) Shotcrete sealing to the part where fore poling is already installed. (4.2.5) Perform fore poling (4.2.6) Shotcrete of all excavated face are completed by sequence #(1) through (5).
5.3 Wire mesh
(1) Selection of wire mesh (1.1) The main purpose of using wire mesh shall be for the following reasons. Improvement of shear reinforcement or adhesion, or to avoid the coming off during or after construction at expanded original soil base. (1.2) Shotcrete adhesion wire mesh shall be installed at original soil base and shotcrete of original soil base executed. (1.3) For improving the shotcrete resistance force, φ4.8×100×100mm shall be used for reinforced material of shotcrete. (2) Fixing the wire mesh (2.1) Wire mesh shall be fixed tightly to avoid movement and vibration during work. (2.2) For sediment tunnel, fix pin should be hammered and fixed into original soil base before primary shotcrete. (2.3) For the rock tunnel, fix pin should be bended into L shape and placed on during primary shotcrete.
- 20 - (2.4) Mesh shall be fixed so that interval is not wider than 15mm from excavated surface. (3) Overlapping method of wire mesh Joint part of wire mesh shall be connected one another by overlapping more than 1 slating of longitudinal direction (10cm), and 2 grating of transverse direction (20cm).
5.4 Shotcrete
5.4.1 Selection of pouring type
For selection of pouring type of shotcrete, soil condition, tunnel length, excavation type and water availability shall be reviewed including economics, applicability and health sanitation.
5.4.2 Functions for pouring equipment
(1) Selection for Pouring equipment shall be made which is safe for internal pressure and capable of conveying continuously the required mix material. Wet type should be selected except for special circumstance. (2) The capacity for attached equipment and accommodations shall be able to provide for concrete pouring machine, to attain its maximum capacity of pouring.
5.4.3 Material selection
(1) Cement should be Portland cement properly based on KSL 5201 (2) Aggregates (2.1) The mix should be approximately 60 : 40 for coarse and fine aggregates for accurate mix, based on the grade curve of coarse and fine aggregate site test, coinciding very close to optimum grade distribution. (2.2) The curve shall be of smooth line within range of mixed grade curve line without rapid change.
- 21 - (3) Accelerator (3.1) Accelerator shall be used to get the early strength of shotcrete and ratio of accelerator is to be based on 5% of cement weight. Where water is extant the ratio may be increased with the Supervisor's approval. (3.2) Accelerator shall be used having best proper quality, which meet with aggregate requirement and its kind selected in accordance with test result of concrete strength.
5.4.4 Mixing
(1) Mix of shotcrete shall be based on the following chart.
(2) Compressive strength for shotcrete shall be maintained more form 100kg/㎠ within 24 hrs, and more than 210kg/㎠ for 28 days strength. (3) Mix examples are as shown in the following chart but should be readjusted upon testing.
- 22 -
5.4.5 Material control
(1) Accelerator shall be Properly stored without any quality change. (2) Aggregate of coarse and fine shall be stored separately, and shall not be effected by rain or snow, and stored to avoid freezing during the winter.
5.4.6 Weight mix
(1) Weight of material must be by mass (2) Mixing shall be made sufficiently to mix material uniform. (3) Mixing shotcrete shall be selected, requiring initial and long-term strength, bounding property, and contractibility, in order to insure good quality of concrete. (4) Construction Contractor shall confirm the details, by test mixing with same materials, which has been used in construction. Test mixing result and material selection test shall be approved by the Supervisor.
5.4.7 Preparation of poured surface
(1) For safe work, such foreign materials as floating stone should be carefully removed, during the construction. (2) In case of water being extant on poured surface, proper drain should be made by guide drainage.
5.4.8 Placing
(1) Shotcrete shall be placed close to soil base as quickly within shortest period, after
- 23 - excavation in order to minimize deformation of soil base. (2) Placing shall not be stopped by mechanical breakdown or stucked pipe. (3) Surface of shortcrete shall be level after shotcreting. (4) Pressure of pressured - air shall be maintained, at proper value for collision velocity of aggregates. And also it shall be based on approximately 2~5kg/㎠ in accordance with transfer distance. (5) In dry method, water pressure shall be maintained at 1kg/㎠ higher than pressure of pressured - air. (6) If thickness of shorcrete is more than 10cm, placing shall be made by multi layer method and constructed to outline surface with conformity. (7) Dispersed repulsion agent during construction shall be cleaned, and cleared carefully. Placing over the repulsion agent is prohibited. Specially repulsion agent should be completely removed and inspected by the Supervisor. (8) Necessary protective measure should be taken to keep nearby facilities from damage caused by shotcreting. (9) During the end of day of dry time, finishing work shall be carried out gradually thin to end part. (10) For hot and cold weather construction, general concrete construction standard shall be followed. (11) For section, where erosion can be expected, caused by water after shotcreting, proper grouting should be performed suitable for site condition to soil base and shotcrete surface for tight adhesion
5.4.9 Reinforcement materials combined with placing
(1) The shotcreting after fixing wire mesh, rebar and steel rib, shall be made without leaving any void on surface of reinforcing material. (2) Material of reinforcement shall have such chemical property as not to leave void when shotcreting, and so fixed not to be moved or vibrated.
5.4.10 Protective equipment
- 24 - Shotcreting workers should wear the protective equipment in order to protect them form rebounding aggregates and dust.
5.4.11 Dust treatment
Place for shotcrete should be dust treated with dust trapping other than ventilation system, if necessary.
5.4.12 Quality control
For shotcrete the size shall be confirmed by test and inspection for the following.
5.4.12.1 Shotcrete thickness
(1) The standards for shotcrete thickness shall be based on design drawing falling within the following value. (1.1) soft and hard rock tunnel : average ≥ design thickness (1.2) weathered rock and sediment : minimum thickness ≥ design thickness (2) The measurement of shotcrete thickness shall be basically performed by inspector, and measurement interval carried out for one cross section within 20m of tunnel length. (3) Number or measurement shall be based on one cross section of 3 places on arch part and one on each right and left side wall. (4) Measurement method by inspector, shall be more than 32mm by diamond drill. And in case of using pin, round nail or round type steel shall be used and installed at measurement places, and the thickness of shotcrete marked.
5.4.12.2 Shotcrete strength test
(1) Sampling method : Mold(l50×150×530mm) for testing concrete bonding strength shall be used in sampling with plate being separated and standing at about 70° for shotcreting from top to bottom so that repulsion agent may come out. After shotcreting, mold top is to be smoothed with triangular edge and sample taken for
- 25 - testing. (2) Testing method : Compressive strength test for each age shall be peformed for the sampled specimen according to KSF 2422 concrete. (3) Direct core sampling method(Sampling after work) : This test shall be performed to confirm quality of shotcrete being actually executed. Sampling method is to take the circular specimen of φ100×100mm or φ50×100mm by core sampling machine, from shotcrete of inside tunnel. However, this method will be difficult for sampling the core if age is not more than 3 days. When height of specimen(thickness of shotcrete) does not satisfy this condition, it is necessary to correct compressive strength test result by height. (3.1) Test age : 28 days (3.2) Test method : KSF 2405 (3.3) Judgement standard and retesting: (3.3.1) Value of average three cores from same place should be more than design strength. (3.3.2) 2 of 3 cores shall be more than design strength and more than 1 cores should not be less than 85% of standard strength. (3.3.3) For the section which did not pass the primary test sample shall be taken for retest from 5m of left and right and judged according to the above standards. In event that result of retest failed the judgement standards, remedial work should be made.
5.4.12.3 Short and long term compressive strength for shotcrete.
(1) Sampling method : KSF 2401 (sampling method for unhardened concrete) (2) Test age : (short -term) 24hrs, (long - term) 3 days, 28 days (3) Curing method : KSF 2404(curing method, to make the specimen for concrete compressive and bonding strength at site) (4) Test method : KSF 2405(compressive strength of concrete) (5) Results : relationship of age~ compressive strength should be shown on graph.
5.4.12.4 Assumption of rebounding rate
- 26 - Calculation for rebounding test should be made by following formula, after shotcreting (approx., 0.2㎥)at site and weight of the concrete (rebounding material) weighed.
5.4.12.5 Quality control standards for shotcrete
(1) If improper shotcrete is found it should be removed and substituted with proper shotcrete as instructed by the Supervisor. (2) For displacement of soil base, it should be measured at any time and particularly carried out after finishing shotcrete and reported to the Supervisor.
5.5 Steel rib
5.5.1 General
(1) Steel rib shall be fabricated in accordance with manufacture design drawing approved by the Supervisor, in advance. (2) The Contractor shall store minimum level of parts on site to avoid delay in works.
5.5.2 Material
(1) Basically the quality of the material for steel rib shall be confirming to standard product of SS 400 (KSD 3503 rolled steel for general structure), however under inevitable circumstance SWS 400 (KSD 3515 rolled steel for welded structure) may be fabricated at factory, upon approval of the Supervisor in advance. (2) Bolts, nut and washers for friction joint shall be complying with provisions of KSD 1010. (3) Steel rib shall be processed for bending by cold working.
5.5.3 Construction time
Steel rib shall be installed as soon as possible in sequence as shown in drawing in
- 27 - order to reduce slackening of original soil base.
5.5.4 Construction
(1) Steel rib should be placed on right position as approved by the Supervisor. (2) In installation of steel rib, necessary measures should be worked out in order to prevent settlement resulting from geological features. (3) When the minimum thickness line is specified, work shall be made to keep the link. (4) Mutual connecting bolt and connecting maternal for steel rib should be fastened tight. (5) Connecting bolt for members shall be tight enough that its joint will not be a weak point. (6) Bottom surface of steel rib shall be installed as close as possible with original soil base, and should be filled with shotcrete where void exists. (7) In order to stick combined supports with steel rib, shotcrete, wire mesh within minimum thickness of shotcrete, rib shall be installed close to excavation surface as far as possible. (8) In case of using the grouted bar or pipe, fore poling, rib shall be prevented from being moved or twisted. Installation deviation shall be within ±5 cm, under such circumstance.
5.5.5 Material storage
Such material delivered to site as steel rib, bolt, nut, washer, steel plate supports and material which are not being installed and steel attached parts shall be stored in designated place by the Supervisor.
5.5.6 Inspection of steel rib
Steel rib shall be inspected at all times. If found abnormal, rib shall be reinforced immediately.
5.5.7 Modified steel rib
- 28 - When it is necessary to modify deformed steel rib it must be changed with the Supervisor's approval.
5.5.8 Adjusted installation interval of steel rib and records
Installation interval of steel rib may be adjusted in accordance with types of rock quality in the tunnel. After blasting with the Supervisor's instruction and make the records for installation of supports and submit it when design change is made.
5.6 Rock bolt
5.6.1 General
(1) Basically types of rock bolt are as follows : overall bonding cement mortar type, cement paste type and resin type. (2) Selection for rock bolt support, shall take into consideration the following matters : strength of soil base, joint, status of crack expanded water existence and extent for boring roughness and reliance for borehole placing, fixity direction, and economics. At this time, 2 or 3 types of rock bolt supports shall be selected for pull-out test before working. The result shall be submitted for approval by the Supervisor before proceeding work.
5.6.2 Major materials
5.6.2.1 Rock bolt
Rock bolt quality shall be selected considering functional effect, design drawing and constructability and basically standard deformed 5D 35(more than 50kg/㎟ of tensile strength more than 18% of elongation) shall be selected except those of facing surface. In case of 25mm diameter, yield strength should be more than 17 ton. However if deformation is more than 20mm at proper strength rock, the product of yield point exceeding 50kg/㎟ shall be used. Also Rock bolt with 25mm diameter is a basic.
- 29 - 5.6.2.2 Bonding material
Selection for bonding material should have following features: proper early bonding force easy to handle and sufficient durability and economics. (1) Resin type (1.1) Material for resin should be polyester resin based or equivalent and provided in capsule type. (1.2) Product expired manufacturing date, shall not be used and it must not be affected by water, salt water, acid and light alkali. (1.3) Resin should have such sufficient strength character, that resistance strength is evidently bigger at least 20% than specified strength of bolt for pull out, displaying bounding strength at earlier stage. (1.4) Diameter of resin shall be more than 27mm with expandable bonding material and compounding of resin shall be as much as 2 times expanded to the point with high initial strength in water. When using the vaporable resin, reduction in bounding strength shall be checked in relation to vaporization ratio. Insertion sequence : quick setting, point fill types. (2) Cement mortar type : Decision for mixing of cement mortar shall be focused on constructability. Mortar consists of sand, cement and additives and w/c rate in 40~50% of mix is a basic. Sand for mortar shall be of good quality conforming to grade distribution less than 2mm and amount shall be adjusted in accordance with surface amount of sand. Mortar cement shall be either portland cement with accelerator in capsule type or equal quality for early setting at initial stage or high early strength cement, shall be used with retarder as additive in order to control mortar handling time, with particular care for construction management. (3) Cement paste type : Cement paste consists of cement milk and accelerator and example of mixing rate is as follows but shall be adjusted through site test depending upon water temperature and water condition.
- 30 - 5.6.2.3 Attached parts
(1) All type of bearing plate shall be of completely being adjusted in order to prevent the spilling fall of soil base with sufficient effect on constraints to soil base deformation by these adjustment. Such adjustment could offer completely tight adhesion regardless rock type or shotcrete surface. (2) Before bearing plate penetrates into shotconcrete or nut penetrates into the plate, plate size and thickness shall be compatible with strength of steel material and shotcrete so that anchor could be broken beforehand.
5.6.3 Construction
5.6.3.1 Construction plan
In construction of rock bolt work, construction plan shall be submitted for approval of the Supervisor indicating schedule, manager, equipment & materials to be used fixity procedure and setting time for fixity etc.
5.6.3.2 General
(1) Fixity for rock bolt shall consider geological condition and construction method in order to achieve proper fixity force. (2) For rock bolt type, pull out test shall be performed at near site of similar geological condition with the site in order to confirm rock bolt strength and test result shall be submitted to the Supervisor for approval. (3) Construction for rock bolt should be made as soon as possible after shotcrete is hardened. (4) Drilling should be made by perpendicular to excavation surface at specific location
- 31 - and diameter and shall be carefully observed to avoid drilling into joint part and that stone dust is not left before rock bolt is inserted. (5) Before inserting rock bolt it shall be cleaned to remove foreign material or rust. (6) If water seeps while drilling, instruction of the Supervisor shall be followed. (7) In the construction of rock bolt to diagonal direction, required degrees shall be secured. However, if it is difficult to ensure the degree, the instruction of the Supervisor should be followed in accordance with condition of soil. (8) If slope of bearing plate for rock bolt is longer than specified accelerater based mortar Plate shall be installed at bottom of soil pressure plate as bearing in order to reduce slope of bearing plate less than as directed. (9) At location of large amount of water such proper methods as drawdown of ground water, water draw off work shall be provided suitable for site condition before execution of rock bolt work. (10) Basically construction method for rock bolting and system bolting shall be used. However when the following increment standards from result of pull out test and soil weight displacement. measurement occur ; additional rock bolting shall be made. (10.1) Deformation of tunnel wall surface reached to about 6% of rock bolting length. (10.2) Enough pull out interval force is not obtained from pull out test of rock bolt. (10.3) Peak value of axial force distribution exists from about more them half of rock bolt length to deep part of soil base. (10.4) Expanded plastic range exceeds length of rock bolt. (10.5) Crack occurs at shotcrete surface by unexpected deformation of tunnel cross section. (10.6) Crown and inner displacement measurements are exceeding the allowable control value and increased rapidly. (11) Bearing plate, washer, and nut shall be assembled, in compatability with ultimate strength of bolt.
5.6.3.3 Construction sequence
(1) Resin type rock bolting
- 32 - (1.1) Drilling diameter : Regular resin bolt diameter is +(6~8mm), and for forming resin, bolt diameter is +(10~l5mm) with it's depth within 50mm of deviation from design depth. (1.2) Resin insertion : It shall be inserted with proper amount of resin by volume calculation. (1.3) Rock bolt insertion : It should inserted rotating the bolt for about 20~30 sec at more than 1,000rpm by auger, pick hammer and drifter (1.4) Bolt fastening : It shall be peformed after checking hardening time by site test after bolt is inserted. (2) Mortar type rock bolt work (2.1) Drilling diameter : Drilling diameter should have (10~16mm) Plus bolt diameter and the depth should have deviation within (+)100mm (-)50mm for design depth. (2.2) Mortar : During mortar insertion, low pressure feeder shall be used (under 3kg/ ㎠) specially when using the capsule type accelerator. (2.3) Bolt insertion : Hammering of bolt shall be made using pick hammer, drifter and guideshell. (2.4) Bolt fastening : It should be performed after checking hardening time by site test after bolt is inserted. (3) Cement paste type rock bolt work (3.1) Drilling : Drilling diameter should have (10~l5mm) plus bolt diameter with depth deviation within (+)100mm (-)50mm for design depth. (3.2) Rock bolt insertion : Seal shall be attached to bolt in order to avoid overflowing of cement plate and fixing the bolt. (3.3) Cement paste insertion : Work shall be stopped if paste is comming out from drainage pipe. (3.4) Bolt fastening : It should be peformed after checking hardening time by site test after bolt is inserted.
5.6.4 Additional work
Additional work should be carried out as instructed by the Supervisor in accordance
- 33 - with soil condition and measurement result if necessary.
5.6.5 Adhesion agent work
(1) For adhesion agent of rock bolt, testing shall be submitted and approved by the Supervisor. (2) Adhesion agent after drilling shall be filled enough to bottom of hole and when inserting bolt void shall not be left.
5.6.6 Construction machine
(1) For rock bolt construction sinker or crawler drill shall be used. (2) Rock bolt insertion equipment shall be air auger with more than 1,000rpm.
5.6.7 Rock bolt pull out test
(1) Scope of application : confirmation of fixity effect (2) Test frequency : Whichever of higher frequency among, one place per 50 or 2 places per 20m. However that should represent each part of ceiling, arch and sidewall etc, as may be selected and directed by the Supervisor. (3) Test equipment (3.1) Prestressing rock bolt and nut (3.2) Center hole jacky and pump (3.3) Expansion gauge and bearing steel (4) Test method (4.1) On selected rock bolt location, gypsum shall be coated to make perpendicualr rock bolt with plate. (4.2) Install the frame and tension bolt. (4.3) Install the center hole jack behind the frame and locked by nut. (4.4) Install the hole that connects between pump and center hole jack. (4.5) Install expansion gauge of magnetic base to frame and fasten bearing steel to tension bolt.
- 34 - (4.6) As pull out strength can be put out by friction force it should be carefully operated slowly by 1ton per /minute when operating hydraulic pump. (4.7) Pull out test result of rock bolt and load deformation curve as above. In the graph straight line is A, curve line is B and last straight line is C. C part can not be expected to have fixity effectiveness for bolt and pull out withhold force seems to be up to D point which cross point of tangent line of A and C. This test is to confirm fixity effectiveness hence it can be assumed that φ 250mm bolt has passed a test if pullout load reaches 12 ton.
- 35 - 6. Steel form work
6.1 Manufacture and construction of formwork
(1) When installing movable frame, manufacture drawing and structure calculation shall be submitted and approved by the Supervisor. (2) Material quality of formwork should conform with SWS 400 and SS 400 and, considering the placing strength of concrete, it must withstand the pressure of already placed concrete. (3) Movable formwork is of steel in tunnel shape operated by hydraulic jack (installed-removed-move)and prompt accurate guide tunnel lining work conducted. (4) At fastening parts of each member high tension bolt shall be used and skin plate shall be installed with inspection door, vibration motor and air vent pipe and concrete pumping pipe. (5) Installation of formwork shall be placed at correct location by center line and longitudinal surveying. (6) Footwork shall be cleaned after moving or before assembling and shall be checked in advance and arranged with the cleaning equipment. (7) After using a few times formwork should be moved out to outside of tunnel and distorted or twisted part repaired. After using certain period of time it should be changed with new steel plate. (8) Wheel parts shall be manufactured easy to change or repair and installed with grease cap to insert grease regularly. (9) As hydraulic jack could be twisted by concrete pressure it shall be safe and stable. (10) Tracks shall be installed on timber with final clamp to avoid deformation during operation. (11) Side plate should be of such structure as to prevent mortar leakage. (12) Minimum thickness of skin plate is 7mm and deformation deviation is 4mm for 2m
- 36 - section and 1mm for form joint. (13) Vibrator for concrete compaction shall be assigned.
6.2 Installation of checking window
(1) After installing formwork checking window shall be provided at crown in eider to confirm concrete thickness and filling. (2) Checking window shall be installed at correct place as shown on drawing. If impossible, it shall be installed at crown part of tunnel center within 3m of transverse and longitudinal direction.
6.3 Inspection of formwork and removal
(1) Before placing concrete formwork shall be inspected by the Supervisor which has been installed already. (2) Removing time of formwork has effect on lining process hence it should not be removed until concrete strength of final placing part (arch crown part)reachs strength to withstand self weight. And it must be removed after approval by the Supervisor.
- 37 - 7. Concrete lining
7.1 General
Concrete lining shall be worked as follows (1) Construction method and timing shall be approved by the Supervisor after reviewing deformation convergence based on measurement (2) Between backside of concrete lining and shotcrete void shall not be formed.
7.2 Mixing condition
(1) Mixing condition for lining concrete shall be based on the following chart.
(2) Mixing of concrete shall be fixed in small unit amount within range of strength, durability, permeability and workability (3) Concrete mixing shall satisfy the design condition and mixing ratio fixed in order to have workability uniform up to overbreakage
7.3 Concrete delivery
- 38 - (1) Concrete should be placed as soon as possible after mixing (2) During delivery it shall not be segregated or mixed with foreign material. Delivery agitator truck is basic as instructed otherwise by the Supervisor
7.4 Concrete placing
(1) After installing formwork concrete placing shall be done after measurement in presence of the Supervisor. (2) Surface should be cleaned in order to avoid foreign material. (3) 1 section of concrete should be placed continually without giving declining pressure up to max. lift of 50cm. (4) During placing it shall not be segregated and vibrator used to fill densely at arch part. (5) Placing time shall be after the tunnel deformation has been converged by measurement. (6) Concrete placing shall be by pump car.
7.5 Rebar assemble and fabrication
(1) Rebar shall be assembled as designed and work of next step shall be proceeded after approval of the Supervisor. (2) In assembling rebar spacer shall be used to maintain correct cover of bar.
7.6 Construction joint
(1) During placing concrete lining expansion joint shall be installed at proper interval considering cross section, size, thickness and temperature differences. (2) During placing concrete lining the construction joint of "V" type shall be constructed in order to guide crack caused by normal drying shrinkage. (3) The construction joint and V type joint shall be constructed on straight line.
- 39 - 7.7 Crown part void
Pipe (φ10mm) should be embedded per 1 span at both end of crown in order to confirm insertion.
7.8 Invert
(1) Before placing invert concrete cleaning and draining shall be carried out for excavation surface and shotcerte surface. (2) In concrete placing compaction shall be performed properly and bottom formwork may be used for high slope. (3) Placing joint shall be installed at perpendicular to invert axis in order to properly transmit invert axis force. (4) Invert concrete shall be installed with joint in order to avoid shrinkage crack of concrete. (5) Invert concrete can not exhibit stress itself hence it must be closured with lining concrete. (6) Construction Contractor shall submit construction plan including existence of invert concrete, thickness, construction method and expansion joint and it shall be constructed after approval by the Supervisor. (7) Construction joint of invert concrete and lining shall be met.
- 40 - 8. Backfill insert
8.1 General
(1) After placing lining, void between back side of lining and original soil base should be tilled with mortar properly. (2) For backfill plan shall be made with regard to quality control of material, construction condition, insert machine and insertion status approval by the Supervisor. (3) During grouting pressure (2~4 kg/㎠) shall be selected for filling crown voids. Work shall proceed upon approval by the Supervisor. Grouting must not be leaked from side wall invert and drainage hole.
8.2 Mixing
Mixing for backfill inserting mortar shall be as below
8.3 Backfill inserting
(1) Inserting shall be peformed as early as possible after lining concrete reached strength which can withstand inserting pressure. (2) Before inserting the obstacles shall be removed for inserting. (3) Backfill inserting shall be inserted by inserting pipe already installed which shall be back up by proper method for concrete or mortar not to come in during concrete
- 41 - placing.
- 42 - 9. Waterproof and drainage
9.1 General
(1) Drain is selected as waterproof for tunnel and it may be changed in accordance with separate design upon the Supervisor's approval when it is necessary. (2) When selecting the waterproof material report shall be submitted to the Supervisor as to supply history of tunneling testing report by authorized institution and construction plan in advance. (3) During construction, construction Contractor must carry out ground water treatment and maintain the drain pipe and water conveyance pipe collecting water well and pumping facility until construction is completed.
9.2 Treatment of construction surface
(1) Waterproofing should be carried out after shotcrete is properly cured. (2) If foreign materials exist on shotcrete surface, it shall be removed completely so that no obstacle exist between waterproof sheet and wall surface. (3) As for pipe, rebar and wire, exposed on wall surface shall be cut and finished with mortar in order to avoid damage of waterproof sheet. Pipe and with shall be finished round with at least minimum 20mm of thickness. Rebar shall be finished at least R=300 mm with minimum 40mm of thickness. (4) Corner should be round surfaced with mortar. (5) If crack found, in structure during construction, it shall be cut in V and filled with mortar. (6) If serious irregularities of shocrete surface exists in tunnel re-shotcrete (at this time size of aggregate shall be 0~8 mm and sand and cement used depending on site condition)shall be carried out.
- 43 - (7) Tunnel and attached facility of connecting section shall have at least 500 mm of curve radius. (8) Sharp surfaces in primary lining concrete of shotcrete shall be adjusted for slackness by mortar. (9) Head of rockbolt shall have 5mm of allowance and shall be finished with mortar of shotctete after cutting and thickness shall be at least 40 mm, max. with 300mm of curve radius.
9.3 Quality
(1) Randelle (1.1) Randelle should have proper structure for support to cloth mat and waterproof sheet. (1.2) Before construction, it shall be approved by the Supervisor. (2) Cloth mat (2.1) Quality of material shall be of polyester polypropylene and polyester. (2.2) Cloth shall have proper drain at full face of tunnel and specialty it hold the increasing pressure by guiding to drain hole naturally. (2.3) It shall be installed with waterproofing sheet between primary lining shotcrete and
lining concrete in order to avoid damage of waterproof sheet that may occur
by movement of exiting rock or during the lining placing. (2.4) Material quality standard
- 44 - (3) Waterproofing sheet (3.1) Material extracted from coal to produce main source material to have a strong resistance·force for underground foreign material like benzene and oil. (3.2) Thickness shall be more2.0mm with quality conforming to KSF 4911 or equivalent. (3.3) Any inflow shall be avoided inside the sheet. (3.4) Any deformation shall not be occurred underwater including salt and oil.
9.4 Construction
9.4.1 Waterproof sheet
9.4.1.1 Treatment of construction surface
(1) Priorities are as follows before waterproof (1.1) Confirm inner side of tunnel. (1.2) Treat shotcrete surface. (2) Confirmation of inner tunnel is as follows (2.1) Correct survey of center line. (2.2) Inner survey in accordance with center line.
- 45 - (2.3) Inner surface and modified cross section should be approved by the Supervisor. (3) Surface treatment shall be performed simultaneously with inner check up. (3.1) Surface treatment is necessary for perfect quality control by avoiding damage of waterproofing agent. (3.2) During surface treatment, water treatment should be performed simultaneously. (3.3) Water should be collected by water collecting pipe and connected to drainage. (3.4) All pipes and pit for thickness survey of shotcrete shall be cut and filled and finished with mortar. Finishing thickness is at least 2cm.
(3.5) In order to install attaching items, all wires shall be cut to fit with primary lining concrete or shotcerte surface. After this, surface should be treated well without having an effect on waterproof sheet.
(3.6) Attached items as rebar or steel, installed during construction, must be cut and
- 46 - finished with mortar or shotcrete. At this time, finishing thickness is at least 4cm and curve radius is more than 30cm.
(3.7) Rock bolt cap· should have 5mm of allowance, and finished with mortar or shotcrete. With thickness of 4cm and curve radius at least 30cm.
(3.8) Between supporting material and irregular surface is readjusted by mortar or shotcrete, with at least 7:1 radio of length vs depth. Finishing cover thickness of supporting material, exposed to shotcrete surface shall be finished by cut or cover below 4cm.
- 47 -
(3.9) Minimum radius for irregularities shall be more than 30cm.
(3.10) If serious irregularities are found on NATM shotcrete surface, it shall be reshotcreted.
(3.11) Curve radius for connecting part of transverse part and connecting part of tunnel inner change shall be at least more than 50cm.
- 48 -
(3.12) Shape surfaces at primary lining concrete or shotcrete surface shall be adjusted with mortar for smoothness.
(3.12.1) In case of separate excavation on top and bottom parts, repulsion agent shall be removed completely and in excavating bottom part soil at joint part shall be completely removed and surface treated coinciding with bottom part of shotcrete. (3.12.2) After surface preparation being finished, it shall be constructed after approval by the Supervisor (cloth mat and sheet installed).
9.4.1.2 Cloth mat installation
(1) Some humidity may be allowed on concrete or shotcrete surfaces. (2) Installation shall be made using Rendelle and fixed by nail and washer. (3) After cloth mat is installed, sheet should be installed after approval by the Supervisor. At this time, if the Supervisor orders to repair, it should be repaired immediately and rechecked. (4) For open cut shotcrete, Rendelle attached to side wall without cloth mat. (lengthwise and crosswise of 1.5m) (5) For drain type of drain method, overlapping shall be made with cloth mat from side wall and invert in order to prevent soil inflow to bottom drain pipe, which will be wrapped by cloth mat.
9.4.1.3 Waterproof sheet installation
- 49 - (1) By heating Rendelle, it should be stuck by hand. At this time, care should be exercised not to damage cloth map by heating. (2) Adhesion with sheet should be performed by double sealing with automatic welding machine. And double sealing part should be confirmed by compressive air or water pressure. The test result should be approved by the Supervisor.
- 50 - (3) Damaged part of sheet should be repaired by pieces of sheet with manual welding, and checked by vacuum inspection method, and approved by the Supervisor. (4) For concrete lining of joint surfaces, sheet protection bar should be installed 50cm wide
(5) Before concrete lining, construction Contractor should request to the Supervisor for checkup of damaged. sheet, and the concrete lining placed after passing inspection by the Supervisor.
9.5 Filter Concrete
(1) Mixing Ratio
(2) Construction Sequence (2.1) Put aggregate on steel plate. (2.2) Spray the necessary amount of water to aggregate uniformly, and wait until water being drained out. (2.3) After water has drained out, only surface water will be left on aggregate. Concrete
- 51 - as needed should be mixed with surface water on aggregates and used.
9.6 Quality Check
9.6.1 Sealing test
(1) Investigation procedure for compressive air (1.1) Close both sides of welded part without baking air, and inflow of compressive air by injection with gauge, and has to be slopped when it reaches to 1.5 ~ 2.0 bars (1 bar = 1.02 kgf/㎠). (1.2) Pressure should not be dropped during 5 ~ 10 min after stop of inserting. (2) Vacuum test (2.1) For test procedures for vacuum test, spray test liquid to test section and carry out the vacuum test. (2.2) Improper welded part will accompany bubbles and should not be occurred at 2,000mm/Ag (1mm/Ag = 0.13592 kgf/㎠) of vacuum pressure. (2.3) Necessary equipment for test should be provided by construction Contractor until the test finished. (3) Inspection and remarks (3.1) Inspection and test, can be sampled by at his/her own opinion, and it should be approved by authorized institution. However, if test can not be made by authorized institution, it must be carried out with manufacturer's own equipment evidenced with quality guarantee paper, in lieu of authorized institution. (3.2) Every each roll of product, should be indicated with wrapping paper, indicating name of product, manufactured date, name of manufacturer and size (depth × width × length).
- 52 - 10. Waterproofing for the open cut type of tunnel
10.1 General
(1) This specification shall be applied to waterproofing of open cut type tunnel structure. (2) Construction Contractor must select experienced expert and approved by the Supervisor. And this expert should be resident at site for construction control. (3) If water leaking is occurred after construction, it should be reconstructed with approval of the Supervisor. (4) Before construction, bottom of concrete should be cleaned in order to avoid inflow of foreign materials. (5) It should have good durability against acid and alkali insuring waterproof effect. (6) Steel should not be corrosive, and easy to construct with proper adhesive.
10.2 Construction of asphalt waterproofing sheet
10.2.1 Construction preparation
(1) Water content for concrete and mortar should be as low as possible and not only proper curing provided but also complete drying. (2) Construction surface should be finished with smoothness. (3) For corner part, it should be round surface with cement mortar. (4) Before construction, crack location should be filled and cured by mortar with V cut.
10.2.2 Primer
Asphalt primer is first using product for proper adhesive on surface of concrete, cement, mortar and steel pipe. (1) Asphalt primer should be applied by brush or roller.
- 53 - (2) It should be applied with conformity over all surface by 0.4ℓ/㎡ of primer and dried properly. (3) Since water can be penetrated by primer only, it must be reapplied after well dried. If rain or exposed for long period, sheet is to be attached. (4) After primer applied, dried condition and attached time for waterproofing sheet are different depending on temperature, humidity and bottom surface material quality, however, generally it should be same. After primer applied, waterproofing sheet should be attached within 2 hours from finger check.
10.2.3 Construction of waterproofing materials
(1) In case of stripping agent being attached to waterproofing sheet, stripping agent should be pulled out from end. And the attachable part (rubber asphalt) attached to construction surface and one person should pull the stripping agent and the other person should pushing the attached sheet for construction. (2) Waterproof sheet should be constructed by overlapping 10 cm wide and overlapping part should be heated by torch lamp or propane burner and attached rigid. (3) Checking the sheet joint condition and attached condition, and approved by the Supervisor. After this, sheet protect mortar(t=30mm) placed and rebar assembled placing the bottom slab concrete. (4) For waterproofing protect wall and end part of bottom, it shall be made 50~60mm of radius by mortar and about 20cm of reinforced sheet attached and construct waterproof sheet on it. (5) Point corner of waterproof protect wall shall be treated round, in order to avoid tear, and the corner reinforced with sheet and protect wall should be wrapped by sheet, so that it must have extra 30cm for correcting during wall waterproofing. (6) For construction joint, the sheet attached cutting 30cm wide in advance, and constructed. (7) After finishing, sheet must be protected from impact by outside protect mortar and block(0.5B) or shotcrete applied (poly urethane board) immediately. (8) Following processes (rebar installed, backfill) should be carried out after completely curing sheet protect mortar.
- 54 - 10.2.4 Waterproof sheet attachment
For attaching waterproof sheet, attached strength is increased in proportion to size of attached area between sheet and base surface. Therefore, it is important, that sheet should be constructed without voids, when attached. (1) Cautions during the work (1.1) Shall be constructed from center to both ends, in order to avoid air between base and sheet, and attached closely. (1.2) It shall not be pull out by excessive power for safety after attached. (1.3) It should be prepared with cautions where works are not well ventilated.
10.2.5 Connecting of each waterproof sheet
Connecting for waterproof sheet is of overlap joint. Therefore construction for joint point should be constructed elaborately.
10.2.5.1 length direction connect
(1) For length direction connect, it has 10cm width of self attached overlap surface, in order to attach well. (2) Connecting for partial waterproofing must be overlapped more than 10 cm. (3) In order to. completely absorb primer into sand of attached part it should be connected by pressure and dried. (4) Connecting part should be pressured down by roller in order to avoid detachment at ends. (5) At low temperature (below 5℃), it should be heated by burner after primer is dried in order to improve connection effect at overlap part.
10.2.5.2 Width direction connect
(1) The connecting part of width direction is connected by sprayed sand on surface and asphalt surface. Therefore, it should be attached using sheet as adhesive agent
- 55 - in order to reinforce adhesive. (2) Applied part of sheet adhesive agent (2.1) Using length direction of waterproofing agent (2.2) Connecting part of strengthening concrete
10.2.6 Surface finishing
(1) After construction, the last finishing of sheet is very important, hence sealing should be peformed because as rubber asphalt comes out in melting condition from connecting part about 5mm. Also, sealing should be performed for such weak part as corner, drain, pipe and overlap of sheet.
(2) After the attached work of waterproof sheet, protect layer should be constructed immediately before waterproof layer is damaged. (2.1) Treatment temperature of waterproof sheet should be more than 5℃. (2.2) Sheet cutting should be performed with fully understanding of attaching direction and size before construction. (2.3) Pulling out smooth in horizontal direction with stripping paper and do correct
- 56 - direction, applying simultaneously attaching pressure. (2.4) After attaching, it should be rolled from center to each end by rubber roller in order to not leave air inside sheet. (2.5) if constructed underground or residential area, it is necessary to do thermal attaching by torch lamp.
10.2.7 Size of waterproof sheet (asphalt based)
(1) Size of waterproof material
(2) Basic material consists of synthetic fiber, cloth mat or film. It should be roll type with special treated asphalt to one side or both side. (3) Adhesive surface of waterproof material should be kept attached with the adhesive agent. (4) Adhesive of waterproof material should be adhesive by self adhesive power. If extra adhesive needed, necessary materials should be provided. (5) Quality test should be peformed at authorized institution and also satisfy following items. (6) Test method for adhesive strength of waterproof sheet (6.1) Adhesive strength between sheets (6.1.1) Store 16 hrs at 20℃±2℃ connected with 40mm overlap for 150mm length × 40mm width of 2 sample pieces. (6.1.2) Adhesive agent or method should be used as indicated by manufacture. (6.1.3) Measure max, load with 100mm interval and 200mm/min tension velocity.
- 57 - (6.2) Adhesive strength between sheet and bottom surface : it should be stored for 168 hours with test temperature 20℃±2℃, for samples of 100mm × 60mm and 100mm × 40nm. All material should be asbestos slate (KSL 5115) or equal products. Adhesive agent or method should be as directed by manufacture. Measure the maximum load by 200mm/min of tension strength and 100mm of interval.
- 58 - 10.2.8 Cautions during handling
(1) It should not be soaked by rain, during delivering or storing and stripping paper not damaged. (2) Waterproofing sheet should be stored in standing position as well as while in transport.
10.3 C. E. C. B (Ethylene Copolymer Bitumen) waterproofing sheet
10.3.1 Introduction
It is made from coal. Installation of this sheet is as follows. Put Randlle into wall surface with the waterproofing sheet fixed and attached by a soldering iron. It is 2 layer waterproofing (cloth mat and membrane)for tunnel and 1layer for open cut with Randelle and membrane only.
10.3.2 Construction surface preparation
(1) Construction should be carried out after proper curing of concrete. (2) If foreign materials are existing on concrete surface, it should be removed completely between waterproofing sheet and wall side. (3) Pipe, steel and wire exposed on wall side should be cut and finished with mortar, in order to avoid corrosion of waterproofing sheet. (3.1) The pipe, steel wire should finished round by 20mm of minimum thickness. (3.2) The rebar should be finished in R=300.0m by 40mm of minimum thickness. (4) The corner should be made round with cement mortar. (5) If crack found at structure before construction, it should be repaired by V cut filled with mortar. (6) If serious irregularity at shotcrete surface in tunnel exists, reshotcrete (at this time size of aggregate should be 0~8mm and it also may be use only sand cement in
- 59 - accordance with site condition) should be performed. (7) The curve radius of connecting parts of inner section and tunnel connecting part should be minimum 5,000m.
(8) The shape surface of lining concrete or shotcrete surface should be adjusted by mortar smooth. (9) The head of rock bolt should have 5 mm for allowance and after cutting, it should be finished by mortar or shotcrete with min 40mm of thickness, max. 300mm of curved radius.
10.3.3 Quality
(1) It should have strong resistance against underground organic foreign materials as benzene, oil. Because this material is mainly extracted from coals. (2) It should be confirmed that thickness is 1.7 ~ 2.0mm with tension of 85kg/cm and elongation rate of 550 %. (3) Any water inflow should be avoided.
(4) Before concrete placing, the damage of sheet should be checked. (5) It should not be deformed by any ground water (organic foreign material as salt, oil).
10.3.4 Construction
10.3.4.1 Construction for cloth mat (tunnel part).
(1) Some humidity on concrete or shotcrete surface may be allowed. (2) The cloth mat shall be peformed by rendelle to concrete and shotcrete surface, fixing with nail and washer. (3) For open cut type structure, it should be attached by Randelle without cloth mat, to side wall (1.5m by lengthwise and crosswise). (4) In drain method, it should be installed by overlap with cloth mat from side wall and invert, in order to avoid soil inflow to drainage pipe at bottom.
10.3.4.2 Construction of membrane (tunnel part)
- 60 - (1) The attached waterproof membrane should be peformed by soldering iron. At this time, should be careful not to damage structures in near area. (2) The soldering iron should have more than 600℃. (3) The attached membrane should be peformed by double sealing with automatic welding machine and checked by compressive air, and approved by the Supervisor.
(4) Overlapping part will be 80mm, while attaching waterproof membrane. (5) For damaged part of waterproof membrane, it should be repaired by pieces of waterproof membrane with manual welding. (6) For installing wire mesh, Randelle should be installed on the waterproof sheet installed already. Spacer shall be used to maintain necessary interval.
- 61 - (7) To joint surface of lining concrete, protection paper for waterproof sheet should be installed 50cm wide.
10.4 Bentonite waterproof sheet
10.4.1 Introduction
The sodium based bentonite, makes perfect impermeability with gel condition under consolidated hydration condition. If waterproof layer is damaged, it can be ill-tempered by itself with more than 13 time high expansive force, therefore it will be maintained continuously and applied for waterproof of underground structure.
10.4.2 Preparation of construction surface
(1) The water content for concrete, mortar should be as low as possible, however, it can be performed after minimum concrete. (2) Construction surface should be finished level without any irregularity. (3) For strengthening for corner appurtenance material should be used. (4) The structure crack should be strengthened by mortar filled curing or appurtenance material.
10.4.3 Construction for waterproof layer
(1) The bentonite waterproof is fixed by concrete nail and washer only. (2) The beutonite waterproof is to be overlapped by bentomite layer at joint part in 5cm. (3) After the sheet attached, it should constructed as naturally in order to achieve the safety. (4) During the construction of underground structure, it should be careful that bentonite is not expanded at early stage by rain or humidity.
10.4.4 Strengthening for corner part
- 62 - For using the bentonite waterproof sheet, it should be strengthened before construction using bentonite appurtenance material in order to increase durability and effectiveness of waterproof layer. Strengthening part is as follows ; (1) Joint part of structure - Using appurtenance material of bentonite. (2) Corner part of structure - Using appurtenance material of bentonite. (3) Joint parts like entrance, corner, etc.
10.4.5 Construction for finishing part
For final finishing part of bentonite, it should be attached and fixed by finish bar, and appurtenance material of bentonite.
10.4.6 Size of bentonite waterproof sheet
(1) Size of waterproof material
(2) Storing and handling method (2.1) Basically, it should be stored inside of building or temporary facility (if stored outside, it should be placed on timber and must be provided cover) and also not direct contact with rain or water) (2.2) Special care is not necessary because it is not harmful chemical.
10.4.7 Supplemental material of bentonite waterproof sheet.
(1) Sealing material for strengthening. (2) Raw material of bentonit for strengthening. (3) Finishing bar. (4) Finishing tape for connecting part of waterproof layer.
- 63 - 10.5 Water slopping plate
(1) Construction joint, through type slab, and expansion joint should be installed as shown in drawing with rubber type water stopping plate in order to meet KSM 6518. The material should be product of special rubber and high polymer in order to maintain consistency of material. (2) The water slopping plate should be conforming to the following KSM 6518 test method and must have more than following value.
(3) The elastic rubber should be sufficiently maintained under water expanded condition, and should maintain the water expansion under repeated wet and dry condition. Durability should be same as general natural rubber product. (4) Water withstand pressure should be more than 5 kg/㎠. (5) The location of water stopping plate should be properly prepared in advance, applying adhesive agent to concrete surface and water slopping plate and pressed down for adhesion. However, place of water and humidity, should be fixed with concrete nail at 25cm interval. (6) The joint at connecting part or joint at crossing point of water stopping plate, where any opening should not be existed shall be overlapped more than 50cm. (7) To avoid the irregularity on existing surface during concrete placing vibrator should be used in order to keep evenness of surface.
- 64 - 10.6 Protection mortar and concrete
(1) For protection mortar and concrete, design drawing and following items should be followed. (1.1) Protection mortar and concrete should not be damaged on existing waterproof layer. If it has been damaged, it should be repaired. (1.2) For mixing of protection mortar, the following chart should be followed as standard.
(1.3) Protection mortar and concrete should be poured immediately after cleaning of surface.
10.7 Waterproofing for the connection part between NATM and open-cut area
(1) For slope difference in lining concrete between open cut and NATM part, it should have ratio of 1 : 5 and surface prepared by mortar fill. (2) For waterproofing open cut asphalt sheet, it should be overlapping with more than 1m from end point of NATM slope preparation. (3) For double waterproofing to ECB sheet at NATM part, it should be overlapped with more than 2m, after waterproofing of open cut. (4) Curing the concrete placed at NATM open-cut part, should be provided with guiding water channel as designed. (5) Shop drawing
- 65 - - 66 - 11. Entrance
11.1 Location and type of entrance
(1) For deciding entrance, it should be reviewed properly with having regard to adjacent structure, sliding, slope failure, etc. (2) At entrance, the deflecting slope and large cutting should be avoided. For type, it should have good harmony with surrounding landscape. (3) In general, the type of tunnel entrance consist of surface-wall and protrude type, considering topography, soil condition, drain plan and harmony with surrounding.
11.2 Drain preparation for tunnel entrance
(1) Before the excavation of tunnel entrance, accurate investigation should be peformed for slope, topography of doubtful of water inflow and measures should be made like ridge gutter and slope water channel in order to avoid water inflow into tunnel entrance. (2) Drain plan should be made, that water adequately flow via collecting water basin from rock culvert.
11.3 Construction for tunnel entrance
(1) The tunnel entrance concrete lining should be strengthened by rebar with a certain interval because bending moment and tension force apply to tunnel entrance. (2) Specially, construction Contractor should show a proper construction method for approval by the Supervisor with regard to slope failure, soil settlement, insufficient bearing power of ground, and sliding. (3) If any Problem occurs to tunnel entrance construction, necessary measure should be
- 67 - made immediately. (4) The tunnel entrance shall be constructed with a ground view of elegance.
11.4 Backfilling for open cut part of tunnel
(1) Backfilling for open cut tunnel section shall be peformed in sequence that has been shown on the shop drawing.
(1.1) Compaction management (1.1.1) For consolidation control, lower side of tunnel open cut area of narrow width, should be tested where PBT test is difficult to perform. (1.1.2) The top of open cut tunnel is easier to perform the PBT, therefore, it shall be controlled with K30 of bearing capacity factor.
(2) Standard for using material
- 68 - (3) Cautions during construction (3.1) Water collecting device of φ300mm shall be installed at bottom in order to drain - leaked water. (3.2) Aggregates for drain layer shall have φ5 ~ 63mm of grading and should not be damage the waterproof material. (3.3) It shall be so carried - out that height difference of both side tunnel be within 1m. (3.4) Height of one layer of backfill shall be less than 30cm and performed until it reaches to certain compactability. (3.5) Care should be exercised, that structure has a one-sided pressure by backfill material. (3.6) Small compact vibrator shall be used down to 2m from at crown of structure. (3.7) Height more than 2m from crown shall be compacted by dozer. (3.8) Pit excavation material may be used for fill-up material, if suitable. (3.9) The near area of structure shall not be backfilled until concrete strength of structure reaches 28 days strength. (3.10) Backfilling shall not damage waterproof material (3.11) Compaction equipment and method should be avoided which could create excessive soil pressure.
- 69 - 12. Monitoring
12.1 General
(1) Monitoring is a means to secure safety in work process and aims to contribute toward economical accomplishment of work, by gathering data in earlier stages and reflect those into designing, constructional work and design change. (2) First of all a measuring plan shall be prepared for submission to and approval of the Supervisor. (3) The supplier shall install measuring equipment at places as prescribed on design drawings, specifications and maintain and manage equipment avoiding any inconvenience in collection of measured data. When feasible, appointment of measurement specialists to perform these activities, including data collection, establishment of counter measures shall be recommended. (4) The Contractor shall organize and operate a task force team for measurement work. (5) The Contractor shall appoint and operate a men-in-charge to carry out various tests as specified.
12.2 Measuring plan
(1) The Contractor shall beforehand establish a systematic measurement plan based on preliminary surveying, conducive to the design and work process, considering measurement objects, scope and objectives of tunnels, conditions of original subsurface and the jobsite environment. (2) Rational operation plan for measuring management shall be made in order to collect high quality measuring data for prompt and correct analysis for application to jobsite.
- 70 - 12.3 Selection of measuring equipment
(1) There are numerous measuring equipment developed and available worldwide, and selection of appropriate equipment fit to application is not easy. Therefore special attention in gathering information, and evaluation of equipment are mandatory for successful selection. (2) Following shall be taken into consideration for selection of equipment. (2.1) Accuracy, degree of repeated accuracy, sensitivity, range and reliability for measurement purposes. (2.2) Simple and solid structure and easy installment. (2.3) Competitive price (2.4) Self-calibration or easy self-calibration capacity against temperature, humidity and
- 71 - other impact. (2.5) Simple calculation, analysis system of measured values. (2.6) Provision of self-verification mechanism for measured values, as far as possible (2.7) Durability of connecting tubes or cables between equipment and terminals against physical and chemical reactions. (2.8) Surface terminals stability against weather changes and physical damages. (2.9) Able to withstand corrosion or electric interference. (3) Simpler mechanism with less operating part shall be preferred to complex one. (4) Special attention shall be paid to calibration procedure and its frequency because exact results are not to be expected despite utmost efforts in measurement and analysis, if equipment has built-in defects. (5) At important places instruments shall be kept in sufficient number so that measured values will not become worthless by break-down of one or two machines. Always keep in mind to be careful for equipment's possible break-down or trouble. (6) Extra numbers of reserve equipment shall be provided for equipment's trouble or for calibration when it is anticipated that measured values may surely exceed limits of preset measurement range. (7) The following is a list of instruments being used worldwide for tunnel work, as classified according to use, operation mechanism, using material and others.
- 72 - 12.4 Measurement management system
Systematic measurement process shall be organized for prompt correction, supplementation of prearranged measurement and evaluation, correction of design or work process.
- 73 - (1) Results of measurement shall be filed and recorded in easily understandable and orderly way on diagrams covering progress of work temperature, rain fall and other important environmental factors. (2) Measuring team composed of qualified technicians shall be wholly responsible for
- 74 - measurement. Man-in-charge of measurement shall be kept in jobsite post. (3) Results of measurement shall be immediately examined, filed and analysed. (4) Clearly define report system and his scope of responsibility of measurement team.
12.5 Installation of measuring equipment
For full performance of measuring equipment's normal functions precise installation of equipment is mandatory. In this regards, preparation and examination of installing guidelines and checkpoints in the course of installation shall be made beforehand.
12.5.1 Guidelines for installation
Measuring technicians shall obtain from the manufacturer installation manuals for each equipment, examine them closely and be fully prepared for possible problems in connection with installment, taking counter-measurement if necessary. Installment manuals shall cover the following matters. (1) List of equipment and its parts needed for installation. (2) Diagram of equipment layout system to check correctness of each equipment's arrangement. (3) For devices requiring drilling, details of drilling conditions.(maximum or minimum of drilling size, coarseness of drilling wall face) (4) Detailed procedure for equipment installation.
12.5.2 Staged installation procedure of equipment
There arise many problems in the course of installation, since it shall be done while main work is in progress. Installation may also be directly influenced by the environment facing unexpected problems. For smooth installation of equipment mutual cooperation system shall be established among the measuring team, the Contractor and the Supervisor. Generally, contents of check points for installation is as follows. (1) Examine manuals both for installation and for equipment operation submitted by the maker.
- 75 - (2) Be fully familiar with every equipment, material, its parts and others, necessary for installation. (3) Cooperation among the Corporation, the Supervisor, the Contractor and manufacturer as set forth by the contract shall be guaranteed. (4) Preventive measures shall be taken against damages which may occur during work process or by changes of the environment. (5) Specifications shall be clearly made defining responsibility, in case of buried structures or cables being damaged during work. (6) To minimize troubles in work, close cooperation shall be maintained between the equipment installing team and the Contractor. (6.1) Use devices enabling quick installation. Exert utmost effort to perform installation work on weekends or by night time, not to hinder main work's proceeding. (6.2) Enough time shall be allowed to installation in the design stage, because installation time at jobsite may take more time than expected. (7) Measures shall be taken enabling to examine precision of equipment during or after installment. (8) Rational installation procedures shall be adopted to obtain precise measurement values. When stress sensors are to be erected, erection time and location shall be modified not to interfere excavation or, not to be influenced by hammering or excavation of nearby materials, which may affect displacement. (9) Jobsite data sheets shall be prepared to record installation process. Recording of matters to be specially remarked and main features during installation period shall be made to confirm installation conditions, for analysis or evaluation of measured values later.
12.5.3 Matters to be considered
(1) Installation of measuring equipment shall be made according to user's manuals, provided by makers. Partial alternations of installing process and method can be made in consideration of jobsite requirements. Measuring technicians shall examine installment manuals beforehand. (2) When drilling of holes are necessary for installation, the depth and direction of
- 76 - holes shall be precisely instructed to drillers. Never leave these matters to their discretion.
12.6 Measurement standards
12.6.1 Measurement type A (normal measurement)
12.6.1.1 Observation and inspection for the inside of tunnels.
(1) Significance of examination : Tunnels are underground structures overlaid on natural strata. Natural strata is of inhomogeneous, incontinuous and irregular dip. There exist wide differences in physical property depending upon location. Whenever new face appears in tunnel excavation, it is necessary to observe the strata situations thereof, take appropriate measures if changes in geological features are verified. Abrupt cave-in and spring water are often closely related to changes of geological features, therefore endeavor to sketch the face condition and to forecast strata conditions. Ahead of the face meanwhile in the already constructed section, strata behavior can influence the 1st stage supports' behavior, therefore development, change and location of fractures shall be closely watched to take proper measures. (2) Observation of face : This observation shall be done, in principle, for each face. When there is little change in geological features one face per day will be observation standard. In case deteriorations of strata is feared to occur, take immediate counter-measures and draw observation diagrams at an appropriate scale describing the following. (2.1) Strata, distribution of rocks, strike and dip. (2.2) Degree of solidity grade, degree of weathering and decomposition, degree of hardness. (2.3) Direction of fracture, frequency, confirmation of gouge and characteristics. (2.4) Location, of fault, strike and dip and degree of fracture. (2.5) Location and level of spring water (2.6) Location and shape of cave-in
- 77 - (3) Observation of constructed section Following matters shall be observed for the constructed section. (3.1) For rock bolt (3.1.1) Location and direction of installation (3.1.2) Slackening of rock bolt and its support (3.1.3) Driven degree of supporting plate within strata (3.1.4) Breakage of cap (3.2) For shotcrete (3.2.1) Thickness, adhesion condition with strata (3.2.2) Fracture (location of origin, classification, width, length etc) (3.2.3) Location, status, quantity of water leakage (3.3) For steel support work - Deformation, location and status of buckling - Driven degree into strata - Contracted deformation condition of contractable support work When deformation is confirmed, record location, type, and extent etc. Draw location chart and make sketches, if necessary.
12.6.1.2 Measurement of tunnel inner strain
As this is done to determine the stability of surrounding strata, adequacy of supporting material, timing for secondary lining and invert based on data obtained from observance and examination of inner tunnels, and crown settlement measurement this shall be made from early stage until inner tunnel strain is contracted. (1) Measurement of inner tunnel strain (1.1) Measurement method : Use measurement devices for inner tunnel use, which can guarantee accuracy needed for this objective, Measuring shall be made applying prescribed tension on the part between measuring points. (1.2) Early stage value : Take earliest possible measurement soon after excavation to get the earliest value. The early stage value shall be those taken within 24hours at least, or before next excavation takes place. (1.3) Measuring points : Measuring points shall be set up not to be moved by tension
- 78 - during measurement. The points shall be securely fixed without being damaged by human or facilities. The cap of the points shall be protected. (1.4) Things to be considered in selection of equipment : Devices for inner displacement measurement shall satisfy the following conditions. (1.4.1) Light weight (1.4.2) Rigid and durable (1.4.3) Accuracy(about 0.01mm) suited to purpose (1.5) Bolts at measuring points : Bolts at measuring points shall meet the following conditions. (1.5.1) Easy installment (1.5.2) Shall have no stress by tension (1.5.3) Shall have identical contact with devices or tapes, every each measurement (1.5.4) Shall be free of dust particles (1.5.5) Shall be priced low
12.6.1.3 Measurement of crown settlement
The measurement is confirm stability of surrounding subsurface condition and primary support, measuring inner displacement. Conventional tunnel work procedure used this parameter to forecast crown overturn. The measurement is as much important as surface settlement since it is much higher than inner displacement under shallow earth cover. In particular, measurement of crown settlement is so important where inner displacement is bigger at which expansion earth pressure is working or horizontal layer is distinctly laid and at expansion layer. etc. Therefore, proper measurement is to be implemented until displacement is reduced. (1) Measuring points (1.1) It is recommendable to use as measuring points that of crown inner displacement measuring points, when inner hole displacement lines are available. (1.2) Where big displacement of strata are present and side pressure is significant, it is desirable to select measurement points at both left and right sides of the arch to measure settlement.
- 79 - (1.3) When steel supports are used, big settlement occurs therefore it is desirable to establish measuring point at proper ratio for steel support work. (1.4) At expansive strata, select and install measuring points at the jobsite at technician's discretion. (2) Measuring process (2.1) Levelling shall be made and absolute height(m.s.b) obtained using bench mark established outside of tunnel. (2.2) Type of staff is available which is light and flexible or plumb metallic device. (3) Considerations for evaluation When surface soil is shallow, measure settlement of surface area first, at short intervals(longitudinal). Simultaneously, crown settlement shall be measured to control strain in front of face. (4) Arrangement of measurement results Measurement value of the crown settlement shall be recorded, together with inner tunnel strain.
12.6.1.4 Pull-out test of rock bolts
This aims to judge fixing effect after rock bolts is being driven. This is very important when the pull-out effect is not much expected at places like unsolidified or sandy ground bed. This test shall be made at earliest possible excavation stage, at suitable places near the tunnel port. (1) This pull-out test shall be compared and evaluated under the following parameters. (1.1) Fixing material and its age (1.2) Shape and material quality of rock bolt (1.3) Length of rock bolt (1.4) Diameter of bolts, relation with the diameter of drilling holes, drilling method, whether pre-stressing is made. (2) Things to be considered at pull-out test of full face fixing type rock are as follows. (2.1) When applying shotconcrete, it is desirable that either rock face will be exposed by crushing concrete, or test rock bolt is wrapped with cloth to conduct testing. (2.2) Make pull out direction consistent with rock bolt axis, using tape washers and
- 80 - others, and take care not to cause twist at bolts, so that exact pull-out resistance value could be obtained. (2.3) Increase the numbers of rock bolts or make its length all the same up to appropriate degree on the places where, like earth and sandy ground, shear strength is weak, and where anti-pullout force is not expected. Considerations also shall be directed to length, diameter, material of lock bolt and strength of fixing material, together with status of spring water, and ground beds. For required length of lock bolts, special attention is needed as there may be difference between values of pullout test and actual axis force distribution. (2.4) The speed of loading at a pullout test shall be 1 ton/m as standard. The test shall be made after preset time elapses, after lock bolt installation.
12.6.1.5 Measurement of surface ground settlement
This aims, like the crown settlement test, to verify stability of ground beds, effects of supporting, as well as to specify beforehand the extent and degree of influences to ground strata by tunnel excavation and thus to prevent damages to the third party concerned. Also important is preliminary inspection (deformation, fracture and others) of structures nearby excavation sites. This surface ground settlement measurement confirms effect of countermeasures taken against settlement, and also supplies valuable data for estimating slack transition in surrounding bed. Measuring points shall be set up longitudinal to excavation direction of tunnel. The interval at the middle center of tunnel shall be based on: For tunnel advance direction, (1) 5.0m distance in case of h
- 81 - generally lasts until the face distance reaches (2~5)D point.
12.6.2 Measurement type B(Measuring at a representative place)
(1) Measurement of underground displacement : Measurement of a displacement within strata at the direction of tunnel's radius is to check the slackening state caused by excavation and to use the data for determination of the primary support adequacy. Generally the length of rock bolts can be determined by underground displacement's distribution at each depth and by axial force of lock bolts. But when shotcrete is only for primary support, backside earth pressure working on shorcrete shall be also estimated. For measurement of underground displacement an underground displacement meter shall be used, which can make multi-point measurement with only one hole. For measurement of relative displacement between anchors, dial gauge type or electric transducer type shall be used. The most important matter in this measurement is to securely fix the anchors to strata at each depth. For fixture mortar type and mechanical type fixture are commonly used. The number of measuring points is variable depending upon strata classification and by the length of bolts and others, but 4-6points for each hole shall be enough for observation of strata behavior. In this connection the deepest points shall be the bolt length plus 2-3m for hard rock. On strata where big displacement is expected, 2times of the bolt length shall be drilled down to the depth equal to the diameter of tunnels. On the other hand, subsurface displacement measurement shall determine whether displacement takes place at the farthest depth, correlation of inner displacement with
- 82 - crown settlement at the same cross section. (2) Measurement of rock bolts : Measuring of lock bolt's axial force is to determine its strength and distribution conditions. Measurement shall be made using a method with which axial strength of pattern bolt can be measured. Full face fixing type lock bolts have no stress at earlier installation stage, then stress occurs in conjunction with strata's behavior. Axial force's strength and distribution shall be derived from the stress, and it is necessary to determine design methodology, pitch, additional driving. For tension type lock bolts, tensile stress is introduced at the installation stage, but as tensile stress change may occur by explosion, vibration at the installation stage, thereafter, axial force shall further be measured and managed. (3) Stress measurement of shotcrete : Axial election stress and tunnel diameter's direction of shotcrete shall be measured by burying a stress-meter within covered underground holes. This is to check stability of shotcrete and necessity of supplementary holes. Devices for this purpose shall be light, simple and easy to handle, and also with marginal error of device itself and that of shape error, considering measuring object's strength and that of device itself. Devices to be Installed on the border of subsurface shall not allow any void between surface and shotcrete. Instruments to be erected within shotcrete shall not have any void between the instrument and concrete. (4) Measurement of underground settlement : The measurement period shall be from the stage when earlier values are measured before settlement impact appears on measuring points following face excavation until the stage when settlement reduced complete. (5) Measurement by inclinometer : Underground horizontal displacement shall be ade by insert type inclinometer installing inclined pipe into subsurface. (6) Measurement of displacement of nearby structures : When any displacement is observed by tunnel work, compare and check with data compiled before work and take appropriate measures by making continuous observation
12.7 Measuring procedure
- 83 - Interval and frequency of measurement shall be based on the following standard subject to change according to jobsite conditions and situations and with approval of the Supervisor.
Note ; ( ) of frequency column shows the case of quick convergence
12.8 Utilization of measurement results
(1) Filling of measurement record : Measurement findings shall be recorded and filed for daily work management and for use of future work program. For this purpose filing shall be made on daily basis whenever measuring is made. (1.1) Summary of tunnel work record : Overall information on tunnel work shall be filled in relation to geological longitudinal profile.
- 84 - (1.2) Observation record within tunnels : Observation records of face sections shall be recorded on standard format. Photos shall be attached if necessary. (1.2.1) Tunnel's name, length, soil cover. (1.2.2) Geological features of face sections. (1.2.3) Excavation date, time, minute and measuring date, time, minute of the earlier stage values. (1.2.4) Measuring parameter. (1.2.5) Name of measuring equipment. (1.2.6) Legend of observation record. (1.2.7) Layout of measuring equipment. (1.2.8) Pattern of supports(thickness of shotcrete, length and numbers of lock bolts, steel supports works deformation allowance, distance of one propulsion). (1.2.9) Record of the date, progress, distance to face. (1.2.10) Extraordinary matters such as face passage, invert excavation, additional bolt driving and others. (2) Utilization of measurement findings for construction work : In the course of construction work various measurements shall be systematically made for use of designing and work, so that the designs at the planning stage may be altered to fit the jobsite conditions, eventually leading to stability of construction, improved efficiency and enhanced constructability.
- 85 - (3) Filling and storing of measurement findings : Measurement results shall be filed and stored for Use of daily work management and for planning of a future construction work plan.
12.9 Report of measurement results
Results of measurement shall be immediately reported. When wide displacement occurs, it shall be promptly reported to the Supervisor for his instruction.
12.10 Handling of measuring equipment
- 86 - Careful handling shall be exerted in installing and transportation of the measuring equipment not to cause any damage. When any-break-down or trouble occurs, it shall be immediately reported to the Supervisor for instructions. Measuring equipment shall be promptly installed before or after excavation.
12.11 Report preparation
Measurement data shall be summarily compiled for report to the Supervisor. In case, conditions of the original surface is quite different from that at the designing stage, a new numerical test analysis (FEM, FDM, etc.) shall be made and the results shall be submitted to the Supervisor.
- 87 - 13. Safety and sanitation
13.1 General
Regulations on industrial safety, industry sanitation standards, rules on explosives handling, and relevant rules shall be strictly followed. Attention to safety and sanitation shall be paid to prevent accidents or injury.
13.2 Lighting
(1) Lighting shall be installed on the job-sites and inside-tunnels, against hazard and danger. Lighting shall be 70 Lux or more. Regular check-up of lighting system shall be done to eliminate any glaring effect. (2) Illumination meters shall be set up in the tunnels, recordings of which shall be reported to the Supervisor.
13.3 Ventilation
(1) Full ventilation shall be made for hygienic and safe work conditions. Gases, dust, exhaust from internal combustion engines and others shall be removed, For this, the Contractor shall take measures to monitor noise, vibration and gas, and file the records for reports to the Supervisor. (2) Observe gas geothermal heat from the original subsurface: If necessary, other measures other than ventilation shall be taken. (3) Ventilation facilities installation plan for underground work shall be made for the Supervisor's approval.
13.4 Drainage
- 88 - (1) Install U-type ditch along cut sections to allow full draining. Maintain always good drainage. (2) Pump-out work shall be made on the reverse slope sections of the tunnel for lifting. Sedimentation tank shall be built to prevent pollution of the crops. (3) For inner-tunnel's reverse slope sections, such as inclined shafts, intermediate collection well shall be provided to drain. Detailed plan shall be prepared for pump capacity, conveying distance, size and location of collection pit etc. for approval of the Supervisor before proceeding with drain works.
13.5 Passage
(1) Safe passage shall be provided for jobsite workers' inner tunnel traffic. (2) Passages shall be made to satisfy the following standards. (2.1) Appropriate width shall be secured for working. (2.2) No dangers causing workers' falling down in the passages, or slippery conditions shall be allowed. (2.3) There shall be no hindrance within 1.8m height from the passage.
13.6 Pollution control
(1) Efforts shall be directed against pollution due to noise, vibration and others in the course of work. (2) During excavation, overturn of surface ground, draught and others which may adversely affect the tunnel environment could be expected, for which enough attention shall be paid.
13.7 Safety inspection
Inspection of subsurface, supporting works and also of machinery and equipment during work shall be made for successful completion of work.
- 89 - 14. Chemical grouting
14.1 Work plan
(1) The liquid injection aims at cutting off water and reinforcing subsurface by injecting liquid on the sections where landslide in tunnels, collapse or differential settlement of the foundation are expected due to slackening strata or washout by tunnel excavation and where NATM system is scheduled against vulnerable factors like weak soil, sand and gravels, weathered zone. (2) This work is to be applied on strata consisting of permeable soil, gravels and weathered weak subsurface. Both rapid and slow-grouting liquid shall be mixed together for improvement of ground conditions. Injection system shall be selected to Prevent loss of liquid and to get the utmost injection effect. (3) The Contractor shall prepare, before the start of work, detailed plans for soil test and strata improvement, and specifications of liquid to be used, work schedule and others for submission to and for approval of the Supervisor. (4) Work plan shall include name of managers, work schedule, materials to use and its mixing ratio, machinery, equipment and its specifications, injection method, location and lay-out of injection holes, injection process and others in details.
14.2 Injection material's characteristics and mixing standards
(1) Injection to be adopted for this work is gel type-, duplex tube-, low pressure method. The mixture ratio is as follows. Any change due to strata distribution shall be subject to the Supervisor's approval.
- 90 - (2) Standard mixture ratio of rapid-type and slow-type grout shall be 1:1. Change may be made depending upon ground condition on the Supervisor's approval. (3) Silicate to be used in grouting solution shall be Silicate No.3 (specific gravity : 1.4), which is used in solution of 40.5 - 41.5 CPS grade. (4) Cement for gel type grout solution shall be used. (5) Gel type injection liquid shall be applied within 2 hours after mixture. (6) Gel time and strength Gel time shall be 6-9 seconds for rapid-agent grout, and 60-90 seconds for slow-agent grout. Of these values, 3-day strength of gel form for rapid type shall be 1kg/㎠, and the strength of slow type is 7kg/㎠. These are subject to change according to strata conditions of the affected area upon consultation with the Supervisor.
14.3 Injection method
(1) Objectives of liquid injection shall be well understood. Work shall be carried out, checking conditions of the subject area. (2) Hole-drilling should be done by the following (2.1) Use φ40.5 - φ55 mm duplex rod for injection (2.2) For horizontal and inclined shafts, holes shall be drilled exactly according to design drawing both horizontally and vertically. (2.3) Location and sequence of drilling holes shall be arranged to get maximum effects for sound ground improvement. For vertical strata drilling, interval of holes shall be 1.0m in main sections, and for face sections of the shaft, about 1.5m (3) One step of injection shall be 50cm, subject to change according to drilling speed and with the Supervisor's consultations. (4) With regard to injection rate for each strata as calculated based on strata test, work
- 91 - experience and relevant documents are as follows. If, in practice, injection ratio integrated calculation standards are not compatible with those of jobsite conditions, alternations are due after consultation with the Supervisor.
(5) Injection speed shall be adjusted according to ground uplifting and others after consultation with the Supervisor. (6) Injection shall be made as follows; (6.1) Under the Supervisor's presence, make a test operation closely checking injection quantity, pressure and others for reports to the Supervisor. (6.2) Injection pressure shall be 5kg/㎠ as standard, but can be changed according to the trial injection results, jobsite conditions after consultation with the Supervisor. (6.3) Injection shall, in principle, start soon after completion of hole-drilling, by commonly-used pull-out method, but can be changed according to jobsite conditions, after consultation with the Supervisor. (6.4) The width of one step, in general, shall be 50cm. (6.5) If big changes in injection quantity appear, report it promptly to the Supervisor. (6.6) Usage and injection quantity of the material shall be reported with verifiable data. (6.7) Prevent unnecessary leakage of grouting work. (6.8) Injection shall be made without causing any reverse flow of grouting, and corroding or damaging the ground floors or nearby structures. (6.9) Standard ratio between rapid grout and injection shall be 5 : 5 basically, but can be adjustable to 5 : 5 or 3 : 7 according to strata conditions. (6.10) Ending of injection shall not be made until after checking of injection quantity and time, and until its adequacy is confirmed by the Supervisor.
- 92 - 14.4 Operation management and inspection
(1) Drilling machines shall be placed exactly at prescribed places and angles, because most of drilling is done in upright or inclined shafts. Before drilling, check existence of any underground structures or buried facilities not to inflict damages to them. (2) Injection management (2.1) A work diary shall be kept for submission to evaluate injection effects. (2.2) After injection for the improvement of ground beds is completed, make jobsite inspections to certify attainment of the objectives and water cut-off effect. (3) Others : Injection machinery shall be kept always clean, checked-out and maintained for eventual future use, especially after completion of injection works.
- 93 - 15. Grouting for tunnel reinforcement (Special chemical grouting by polymer urethane)
15.1 General
(1) Setting operation by polymer urethane aims at reinforcing face or crown of the shafts, by application of, in principle, advanced rock bolt, urethane injection type. (2) This shall be selectively applied to necessary places based on design drawing, to stabilize face or crown sections in consideration of strength of joint and fracture and spring water and others. (3) Trial injection shall be made to determine applying ranges by selecting 2 or 3 kinds of pattern, after reporting to the Supervisor for his approval for operation.
15.2 Main materials
15.2.1 Pressurized insert bolt
(1) Selection of pressurized input bolt's material shall be made considering the objectives and contractibility. When securing stability at face, Hollow type bolt above SD 35 (tension strength: 50kg/㎟, elongation ratio : 18%) shall be used in principle, except at face sections. (2) The diameter of pressurized bolt shall be 27mm or more, while the inner diameter of which shall be 12.3mm at the section between the end and the 1.0m away from it. Bolts shall have a built-in stirring device.
15.2.2 Materials to be pressure-injected
Materials to be pressure-injected shall be Polymer urethane TBU or FCU, mixed type
- 94 - of which has higher primary strength, easy to handle and durable enough. (1) Injection liquid is a mixture of two materials, polymer and MDI-prepolymer based on PPG (polypropylene-glycol). (2) NO liquid shall not be used which elapsed the storage validity date as described by manufactures. It shall not be vulnerable to ground water, weak acid, alkali and others. (3) The mixture shall fully satisfy the following characteristics, when foam-expanded to 4-times in volume. It shall have strong characteristics showing enough strength and adhesion at earlier stages.
15.2.3 Other materials
(1) Machinery and equipment to be used shall be of high pressure type, because abrupt rise of injection pressure may be demanded at face sections of the operation area, where strata change may be expected even at the same location. (1.1) Bolt (1.2) Coupler mixing unit (1.3) Delivery hose (1.4) Pressurized injection apparatus
15.3 Execution of work
- 95 - 15.3.1 Work plan
For the polymer urethane setting method, a work plan describing the followings shall be submitted to the Supervisor for his approval. Manager-in-charge, work schedule, major classifications of machines to be used. pressurized injection procedure, characteristics of and safety of the liquid to be injected, and others.
15.3.2 General
(1) This ground setting method by Polymer urethane shall be applied to attain the utmost effect, taking into consideration of strata condition, applying process and objectives of application. (2) Before application, a trial operation shall be done at the places near jobsite, which have the same strata. This is to determine the range of injection and its effect. The test report shall be prepared for submission to the Supervisor for s approval. (3) This process shall be applied as soon as possible after concrete is set by the 1st and 2nd spray-fixing method. (4) Drilling shall be done on straight line at prescribed points with exact hole diameter, angle, and depth as directed. No stone particles thereof shall be left before insertion of pressurized bolts. (5) When water gushes out in the course of drilling for insertion of pressurized bolts, the Supervisor's directions shall be followed. (6) In the places where much water from spring is expected, countermeasures such as draw down of water level, drilling of drain holes, leading off water to suitable locations and others which are suitable to the jobsite conditions for eventual drainage shall be taken. This shall be done before the ground setting operation. (7) Working patterns are prepared hereunder, based on application charts for each strata class. Suitable Pattern best suited to jobsite conditions shall be adopted after reviewing. (7.1) This applies only for TBU, an injection material of TRI polymer urethane. (7.2) This is classification by operation patterns. Increase or decrease of quantity is subject to strata conditions and after inspection and conference as needed.
- 96 - (7.3) This is based on pitch 4.0mm as standard.
Note) ― : Not applicable △ : Application considerable ○ : Applicable ◎ : Beyond application range
15.3.3 Sequence of operation
(1) Placement of injectors : For installation of injectors, select flat land, away from any influencing factors such as water leakage. (2) Connection of delivery and air hose : Two delivery hoses, 20m each are to be connected to Liquid A and B to shoot out injection liquid and a 3/4 inch air hose to air motor. (3) Hole drilling : Holes shall be drilled at prescribed bolt-insertion points, with bits of 38~42mm drilling diameter, deep down to the bolt's length. (4) Insertion of bolts (4.1) If insertion of bolts is difficult due to breaking off inside holes, either re-drill or insert bolts by putting adaptors to the back side of bolts and by hammering
- 97 - them. (4.2) After insertion of bolts into the holes, make about 50cm thick sealing inside of hole openings with urethane-cauking liquid coated knit cloth for sealing, then confirm solidification of cauking urethane. (5) Confirmation of quid injection operation (5.1) Put liquid into each A, B tank of the injector. Look into the inside of each tank for any foreign substance within. (5.2) Fix the delivery hoses to the mixing unit after confirming shooting-readiness of liquid A and B. (6) Coupling of mixing unit and start of pressurized injection : Start injection after connecting mixing units to the bolt ends, to which shall be attached beforehand one-touch couplers for mixing unit use (6.1) Leakage of injection liquid to surrounding area If leakage is not stopped after 2~3 times manipulation of injectors, suspension of injection shall be recommended. (6.2) Ventilation : Always circulate fresh air with blowers and other means during injection. (6.3) Abnormal pressure : more than specified 30kg/㎠ (6.4) Check quantity of liquid within the tank (7) Ending of pressurized injection : When conditions for the ending are fulfilled, shut off air motor and confirm the lowering of pressure. If residual pressure exists, warning shall be issued to take action. Eventual ending of operation shall come thereafter. (8) Measures after completion of operation (8.1) When pressurized injection is over, detach couplers of the bolt ends. In case the bolts are to be cut off, be sure to use cutting devices only. (8.2) Injectors shall be cleansed after use by prescribed order, and shall be stored in places free from coldness or humidity.
15.4 Injection of pressurized liquid
- 98 - (1) Pressurized liquid of pressured-type bolt shall be submitted together with test certificates to the Supervisor for his approval. (2) Standard injection speed of pressurized liquid shall be 4kg/minute on dischanged volume. Avoid forced injection.
15.5 Machines to be applied
(1) Drilling machine : Drilling machines to which pressurized bolts are to be attached shall be of high efficiency type and be selected in consideration of strata conditions, size of the cross section of tunnels, drilling method at jobsite, length and number of bolts and others. (2) Pressurized injector : Urethane injectors shall be selected after evaluation of working conditions and characteristics of the machines. Air-driven type with maximum shooting capacity of 10ℓ/minute, shooting pressure of 100kg/㎠ and more shall be selected as standard. (3) Compressor : As primary power source of pressurized injector machines with supplying capacity of 4.2 ㎡/minute and up shall be selected.
15.6 General test
(1) Testing matter : Confirmation of solidification effect of improved ground. (Pressurization) (2) Testing material : To be collected by sampling. (2.1) To be done every time when pattern is selected (2.2) Select 3 points at the crown section (3) Testing device (3.1) Compression tester (3.2) Dial guage is not needed when a compression tester is provided with displacement meter. (4) Urethane is an improved solidifying agent of foaming type. Its pressurized solidifying speed shall be around 3mm/minute in consideration of locally different rate due to
- 99 - uneven distribution of concentrated load. (5) The work shall be finished after confirming that most of collected samples of solidified material have shown a big compaction displacement and that they have not yet reached the limits of destruction load. This test is aimed to confirm compression strength of available solidifying material.
- 100 - 16. Temporary electric work
16.1 General
16.1.1 Scope of application
(1) The following specifications provide general standards for overall electric equipment installation work and to be applied to installation of power incoming system and lighting equipment within tunnels, and any matters not specified and included in these specifications shall be worked out based on design documents and drawings. (2) For jobsite management and material management(including supplied material) civil engineering standards shall be applied.
16.1.2 Application of rules and regulations
(1) Work shall be carried out without any violations of the following laws, rules, and regulations(hereunder called as relevant rules and regulations) of Republic of Korea laws and regulations. (1.1) Electric industry law decrees and regulations thereof. (1.2) Electric work law, decrees and regulations thereof. (1.3) Electric equipment technical standards and regulations thereof. (1.4) Electricity supply regulations of Korea Electric Corporation. (1.5) Electric appliance safety regulations. (1.6) Korea Industry Standards. (1.7) Codes, ordinance and rules of relevant cities and community. (1.8) Other related rules and regulations (2) Any discrepancies between drawings and installation specifications shall be referred to the Supervisor for his instruction.
- 101 - 16.1.3 Scope of work
Any work starting from secondary side of power feeder from KEPCO shall be regulated by these specifications.
16.1.4 Incoming power
Incoming power shall be made based on design drawings at designated points from KEPCO supply network. Intake work of electricity shall be started by instructions of the Supervisor, because receiving point may not be specified at the design stage and the points' location may be altered due to possible changes of KEC supply. In-take application request to authorities concerned shall be prepared by the Contractor on behalf of the Contractor.
16.2 Submission of work plan and work diagram
Detailed work plan on electricity, machinery, civil engineering and necessary structures as listed below, shall be submitted before start of work to the Supervisor for his approval. (1) Detailed work plan 0 be submitted. (1.1) Detailed distribution cable layout diagrams for extension part of building structure. (1.2) Detailed layout diagram of overall intake distribution, lighting equipment and floodlight tower. (1.3) Layout diagram of cable tray. (1.4) Detailed earthing diagram. (1.5) Any detailed diagram as requested by the Supervisor. (1.6) Detailed fence installation diagram. (2) Overall fabrication diagrams to be approved (2.1) Overall and distribution feeder : Outer dimension drawing, basic wiring diagram, sequence explanatory diagram, particulars of using parts and others together with relevant standards booklets. (2.2) Any detailed diagrams as requested by the Supervisor. (3) The Contractor shall prepare a work plan for the Supervisor's approval The plan shall
- 102 - include detailed calculated load capacity for drilling, drainage, ventilation, lighting, equipment and other appurtenance together with load capacity for their use. (4) work implementation (4.1) The Contractor shall keep always qualified electricians holding electricity the Supervisor certificate, 2nd class or more as jobsite representative. The Contractor shall submit work schedules before start of work and shall report daily performance of scheduled work and numbers of personnel put into work, to the Supervisor for his instructions. (4.2) Before start of work, the Contractor shall be fully aware of electric and related facility system to prevent possible loss or damage. (4.3) The Contractor shall re-work or take appropriate actions with the Supervisor's instruction, when the work is proved to be insufficient or unsatisfactory. (4.4) The Contractor shall do complementary or necessary work as required technically by relevant rules and regulation even if those are not specified in drawings and specifications(here under called as design documents) with the Supervisor's instruction. (4.5) The Contractor shall prepare technicolor photos (booklets) of finished work, all test performance reports, all measurement lists(insulation resistance, earth resistance and others after completion, for submission to the Supervisor. (4.6) Intake of receiving electricity shall begin 10days before completion of work. Power energizing test on jobsite shall be completed 3days before the completion date of electric work. In this connection the Contractor shall follow the Supervisor's request as is made separately. (4.7) At start of work the Contractor shall complete any procedures of application, permission, testing etc. to authorities concerned (such as KEPCO, Korea Safety Management Corporation) on behalf of the client. All fees and cost for these applications shall be paid by the Contractor except application fees for electric supply request to be made to KEC, which shall be paid by the Contractor. (4.8) Any equipment and materials to be used shall be KS standards. When KS standards are not available certified items or equivalent may be used, with the Supervisor's approval.
- 103 - (4.9) If any facilities are destroyed or damaged by the Contractor side's defaults recovery or re-work shall be made by the Contractor with the Supervisor's instruction. All cost required in this regards shall be at the Contractor’s expense.
16.3 General
16.3.1 Location of facilities
(1) Detailed locations of facilities and cable lines shall be designated and arranged at jobsite, before start of work based on load diagram with the Supervisor's approval. (2) Redundant work shall be prevented by elaborating beforehand other work(civil engineering, building, machine) eliminate mutual intervention. If trouble arises due to lack of pre-evaluation or pre-conference, rework shall be done at Contractor's cost. (3) Concrete bases, cable pits shall be set up considering additional space for future extension of intake facilities.
16.3.2 Waterproof and safety measures
(1) When facilities and cables are to be installed in water or humid places or area, where exposure to inflammables or corrosive gases are feared waterproof, anti-corrosive, explosion-proof measures shall be taken. (2) For cable pits within concrete base for incoming and distribution feeder board squared lumbers shall be laid out with 0.5m interval to prevent buried cables from direct contact with the beds.
16.3.3 Erection of panels
(1) When facilities and panels are Is be erected on concrete bases, they shall be securely fixed using anchor bolts for base after concrete is completely dried out. Examination of the base surface shall be made beforehand to verity defect-free condition. Possible damages shall be completely remedied by the Contractor.
- 104 - (2) In case of erection of facilities and panels on outdoor ground surface, installation level shall be 200mm up above the ground surface. (3) When cable pits are to be erected on concrete beds of incoming and distribution boards, some slope for drainage and setting-up of drain pipes shall be taken into consideration for cable laying. (4) Locks shall be furnished on fences for restriction of access. For safety measures, danger warning posts shall be attached to the fence.
16.3.4 Cable and duct laying
(1) For terminal finish of cables with more than 14㎟ cross section, terminal fittings and enclosing devices shall be used. (2) Connection of facilities terminals shall be used. (3) Intake cables in panels shall be securely fixed to suitable supports so that connected sections shall not to be subject to high pressure. (4) Opening caused as a result of cable laying through panel boards shall be filled with putty or other material, shuttling off humidity or foreign substance. (5) Cable ducts, cable racks, metal ducts going through expansion joints of structures shall have enough flexibility. (6) Short wiring, such as motor connection shall be of water-proof, flexible type. (7) Sheath covering of electric power cables shall be identified as follows. Color mark-bands may be used depending upon circumstances at the ends of connection with each apparatus.
- 105 - For transformer facility, already installed main bus bar phase and color system shall be used. (8) When cables are to be embedded within reinforced concrete slab, cable ducts shall not occupy more than 1/3 of slab thickness. Within slab, no more than 3 cable ducts shall be overlapped. (9) In metal duct laying normal bands shall be used for curbed section exceeding 28C diameter. (10) For duct channels at water and humid places or to be connected to outdoors, anti-humidity and water-proof measures shall be provided building U type ducts. (11) No connection of cables shall be allowed within cable ducts. (12) When cables are to be fixed according to type of lighting, the interval shall be 2m or less. Support shall be provided within 1m, at max, from box or future. (13) For duct channel section tube buried outdoors, where heavy traffic is expected or liable to exposure to other pressure, surroundings of concrete portion shall be reinforced. Work shall start after reporting to and with approval of the Supervisor. (14) Cable tray(600W×300D) shall be of inside rail type and have standard length of 3m Separators shall be installed at 300W point and be laid separately according to high or low voltage. (15) Cable tray supporters shall be erected at 1.5m interval. For fixations of the cable tray on side boards, set anchors shall be used.
16.3.5 Lighting facilities work
(1) Lighting facilities within tunnels shall use 3φ-4W, 380/220V circuit and shall be connected in ABC order. Lighting devices shall be directly fixed high at the center section of tunnels. At the openings of tunnels, fuse-provided switches exclusively for lighting use and with earthing system shall be installed at 1.5m points. (2) Floodlights shall be firmly fixed by bolts, and shall not tremble or sway. Earth terminals of flood lights shall be earthed. (3) Cables to be used between lighting towers floodlight and stabilizer shall be more than 3.5㎟. Cables for lighting devices within tunnels shall be more than IV2.00㎟.
- 106 - (4) Lighting devices to be installed within tunnel's shall be fixed at 15m interval for inclined shaft section and 10m interval for main shaft section on the ceiling(600W×300D) on the sideboard with supports. (5) Cable laying for lighting in the tunnels shall be made first of all on short-distance circuit in inclined shafts. Long distance cabling for lighting shall be made by extending existing circuit to the points designated on drawings, then to be connected to incoming and distribution. (6) For cables coming from cable tray to lighting device PE cable ducts shall be installed using saddles, which shall be securely fixed with pins at 2m interval. (7) Outdoor poles to be erected outdoor and every duct coming into boxes shall be extruded more than 150mm from the base top to cut off water penetration into ducts. (8) Lighting device's angle for outdoor floodlight towers shall fully cover the front and back side of power incoming and distribution board.
16.3.6 Cable laying work
(1) Selection of location : Selection of location selection for underground cables and other items to be buried shall be subject to the Supervisor's approval before start of work. (2) Excavation and backfill (2.1) Before excavation, underground structure and obstacles shall be checked not to cause any damage. Where there are any, appropriate action shall be taken. (2.2) Buried pipework shall be excavated up to the prescribed depth and ground securely consolidated to backfill. The 100mm under pipework and 100mm above the pipework with fine soil and compacted. (2.3) Burying depth of trough under roads and power cables shall be more than1.2m. For other section, 0.6m and up. (2.4) In case of burying underground cable ducts, warning tapes shall be attached at 300mm up point of the cable's crown section. At least more than 1.5 times of the unit length distance shall be secured for overlapping work. (2.5) For cable laying of high-or low voltage, excavation shall be made separate.
- 107 - (3) Unrolling cables from the drum shall be made by inserting steel pipes into the axle hole and then by rotating on the cable jacks or drum supports. In this connection utmost care shall be exerted for the cables not to twist or entangle. Also observe any damages on the cables. (4) All through the route of cable stranding, universal rolls shall be set up for the cables to be stranded through the rolls. For stranding cables at curbed end sections such as crossing points of horizontally or vertically bent sections of rack(duck) or pits shall be more than 8-10 times of the outer diameter of the cables. (5) In stranding, no unreasonable tension shall be applied beyond allowance, in consideration of safety ratio. Tensiometer may be used for observance. (6) When cables are to be cut after stranding, there shall be no shortage of cable length at finishing end. In case of stranding with terminal, measurement of real length using tape is mandatory before cutting. Never cut off the cables by visual measurement or by estimate. (7) After cutting off branching cables, the cut-off section shall be wrapped up by vinyl tapes to prevent water penetration into insulated part. for cables buying or line-connecting purpose, cable joining material should be used.
16.3.7 Earthing work
16.3.7.1 Earthing and rod
(1) Exposed metal frame of every electric equipment, machinery, neutral lines of transformer and others which do not constitute circuit shall be earthed. (2) Earth rods shall be copper of more than 19φ×2,400L. (3) Earth wire shall be bare copper line(HDCC) for underground burying and vinyl insulated line(GV) or vinyl insulated line(IV) for surface-exposed section. Test terminals shall be set up to measure earth resistance. (4) For cable tray, earthing shall be made with bonding jumpers.
16.3.7.2 Earthing wire
Thickness of earth wire is as follows.
- 108 - (1) Earthing work, class 1 : Thickness of ultra high and high voltage earth cable is as follows
Earth booth, lightning rod and other cables shall be more than 14㎟
(2) Earthing work, class 2
(3) Earthing work, class 3
- 109 - 16.3.7.3 Earthing work
(1) Earth rods shall be buried, the upper end of which being more than 0.75m deep under the ground surface. Earthing areas shall be humid enough, free from any source of gas or acid corrosion. (2) Connection between earth cables and earthed equipment shall be secure enough either electrically or mechanically. (3) Lighting facilities in the tunnel shall be earthed by on block earthing system from incoming and distribution board. Floodlight towers shall be earthed individually by earth work, class 3. (4) When earth resistance shown in KEC standards is not available supplementary earth pole shall be installed. (5) Underground earth poles and bare lead cables shall be separated at more than 2m distance from bare lead cables respectively. (6) Sign posts showing classes, grades of earth rod, year, month, date of installation shall be set up near earthing area. (7) For connected sections of earthing lines, connectors and clamps shall be used. For earthing of fences cadwelding shall be made for fence. (8) Earth poles shall be buried underground, where there is enough humidity without any of corrosion from gas and acid. The depth shall be below the normal ground water level(the elevation from which ground water seeps under normal condition). (9) Earthing of fences shall be made by forming closed circuit net of BC 140 at the places about 1m distant from the fence.
- 110 - 16.3.7.4 Manufacturing and delivery
Facilities to be supplied by contract shall be delivered to the places as instructed by the Supervisor. The Contractor shall immediately comply with the Contractor’s application request to KEC for electricity intake. As for inspection demanded by Korea Electric Safety Corporation before receiving power, the Contractor shall be present at inspection sites and follow the instructions, if any.
16.3.7.5 Witnessing and confirmation
In the course of manufacturing and installment of facilities, the Supervisor can be present as needed at his own discretion. Any remedy or directions requested by the Supervisor shall be promptly complied with.
16.3.7.6 Things to be considered within electric system
(1) In designing of panels, related aspects with other facilities within electric system shall be fully considered for safety and reliability of electrical system and for efficient operation. (2) The Contractor shall perform trial operation under presence of the Supervisor after completion of facility manufacturing. (3) Each apparatus, device composing the products shall have mechanical and thermal capacity to withstand any outside conditions. They shall be very safe electrically and conveniently laid out for checking and maintenance. (4) Control circuit's sequence shall follow the Contractor's standards unless specified otherwise. When panels are interlocked one another or with the outside, the function shall be fully satisfactory and sequence composed as simply as possible. Interlock control circuit's cabling shall be finished itself within panel. Cable connection to terminal boards shall be provided even though contacts are not in use.
16.3.7.7 Transportation and trial operation
- 111 - Every manufactured product shall be transported and delivered, In principle in completely assembled state. When delivery in assembled form is not feasible, separate delivery may be allowed on condition that these are to be reassembled under the Contractor's responsibility.
16.3.7.8 Test and inspection
Test and inspection shall be made at the Contractor's cost. For delivered distribution panel, test by public organization's or the Contractor's shall be made before submission of test certificate.
16.4 Manufacturing specifications
16.4.1 Incoming and distribution panel
16.4.1.1 Applicable rules and regulations and standards
(1) Facilities and equipment of this work shall be manufactured based on up-to-date design using up-to-date material. All facilities shall satisfy the following rules and standards. If no governing rules and standards are available, recent technical precedents shall be followed with the Supervisor's approval. (1.1) KS : Korea industry standards (1.2) KEMC : Korea electric maker's cooperative code (1.3) Technical code for electric facilities (1.4) Indoor cabling rules (1.5) Korea Electric corporation's standards (1.6) Rules for electric distribution (1.7) NEMA (2) Manufacturers shall observe relevant rules, regulations and standards in regards to designing, manufacturing, test and inspection, and have sufficient capacity needed in operation of these facilities.
16.4.1.2 Drawings to be submitted
- 112 - (1) Structure drawings (1.1) Outer box arrangement and layout plan of facilities and equipment (1.2) General plan, front view plan, cross section (1.3) Other necessary drawings (various technical data and data sheet) (1.4) Any other drawings (technical data and data sheet) as needed. (2) Wiring diagram (2.1) Single wire diagram (2.2) 3 wire diagram (2.3) Control circuit diagram (sequence diagram) (3) Specifications (3.1) Manufacturing specifications (3.2) Equipment specifications and catalogues
16.4.1.3 Minor alternations
(1) In the course of fabrication of electric distribution boards, alternations are allowed only under inevitable circumstances, such as jobsite's finish work situation, change of locations, simple alternations of wiring and others with the Supervisor's approval. (1.1) Structure test (1.2) Performance test of equipment (1.3) Sequence test (1.4) Voltage withstand test (operating frequency test) (1.5) Other test as needed (2) When disqualified or defective and defaults are found in the course of test, inspection and trial operation test, immediate remedial measures shall be taken for re-test or re-inspection at the Contractor's account.
16.4.1.4 Specifications of incoming and distribution panel
Outdoor self-standing panels shall be so structured as to attach or withdraw wiring from under neath. Cable holes shall be made fitting to cable pits on the concrete base. (1) Structure
- 113 - (1.1) Swtch gear panels shall be of enclosed metal clad steel-structure consisting of panels of 2 and more metal combination and be durable enough for use in mountainous area which are bended or reinforced by pressed ribs as needed. (1.2) Every metal structure, except charging parts shall be assembled to allow electrical connection.
(1.3) Apparatus enclosed shall be cut off by earthed metal sheets and designed to allow easy maintenance and check-up. (1.4) Switch gear panel shall be designed to prevent temperature rise due to direct sun rays. (1.5) Detachable protection sheets shall be erected on the upper or back part of each separate compartment for easy access to bus, CT and power cables without exposing any other circuit which may be charged at that time. (1.6) The Contractor shall furnish steel base and bolts. If buried into the floor or within structural concrete, detailed layout plans of which shall be prepared for submission. (1.7) Heaters shall be provided in switch gear panel to eliminate humidly. When heat from enclosed apparatus exceeds the radiation capacity of heaters, thermostats shall be installed for automatic shut-off of heaters. (1.8) Each charging part section shall have enough insulation space and shall withstand expected impact voltage. Every charging part shall have insulation capacity drop for a long period of operation. (1.9) Devices within panels shall allow inspection without opening the door. (1.10) Unless specified otherwise the size of a panel shall be subject to the
- 114 - Supervisor approval upon the Contractor's recommendation. A panel may be separated into suitable sizes for easy transportation. (1.11) Each panel shall be furnished with receptacles, lighting lamp and control circuit respectively. (1.12) Auxiliary relays, terminals, wire, name plates and necessary devices with spare parts shall be housed within panels. (1.13) Locks shall be fixed to the panel door handles, and shall endure frequent openings and closing of the door. (1.14) Door hinges shall have enough strength. Door stopping device shall be furnished. The undersides of switch gears panel shall be detachable for cable work or check up. (1.15) Ventilation opening shall be provided within switch gears panel against temperature rise beyond limits. Anti-dust measures shall also be taken. (2) Painting (2.1) Exposed faces of iron or steel structured panels or other equipment shall be painted with anti-corrosive paint. Panels shall be painted by electro static power coating method. More than 3 anti-corrosive paintings and more than one finish Paintings shall be applied. (2.2) Paint to be used shall be water-proof, acid resistant and have durability. Unless specially described paint colors shall be based on KEMC 1104 code as follows. (2.2.1) Outside of indoor equipment : 7.5 BG 6/ 1.5 (2.2.2) Inside of outdoor equipment : N7 (2.2.3) Inside of distribution box : 5Y/ 7/ 1 (2.2.4) Frame of panel meters : No. 2.5 Y 8 / 2 (2.2.5) Knob of the switch : No. 7.5 BG 3 / 3.5 (2.3) Paint material for touching-up shall be supplied together with switch boards delivery. (3) Bus bar (3.1) Material : Copper wire with more than 98% conductivity. Current capacity shall be more than short current value. (3.2) Surface treatment : Silver dipped for bolter conductivity. Phase distinction shall
- 115 - be made with contractable tubes. (3.2.1) R phase : red, 5 phase : white, T phase : blue, N phase : black (3.3) Primary bus bar shall be installed in compartment inside panel. (4) Earthing bus bar : Main bus bar shall be made for common earth system. The lower part shall be arranged for series of box and use a bus more than 5T × 30mm. For high pressure feeder, buses of having capacity to withstand precalculated short current strength or corresponding strength shall be selected. (5) Nameplates and indicting light (5.1) Each board shall be attached with milk-white color acryl nameplate, describing with black letter engraving the name of the board. Portable danger warning posts and operation and no-operation lamps shall be also installed. (5.2) A plate describing the following shall be erected on appropriate place. Manufacturer's name, manufacturing year, month, date, and manufacturing number and type. (6) Testing terminals : Each distribution panel shall be furnished with CTT, PTT terminals to measure current and voltage. (7) Insulation shutter and draw-out : Vacuum breaker enclosed in very high voltage cubicles shall be provided with drawout devices and isolation shutters. Power fuses shall be installed within the panel. FRP insulation partition shall be installed to cut off arc from each panel. (8) Safety guard : Within each panel protective nets shall be provided to safe guard human and animals. (9) Phase indication (9.1) R-phase : red, T-phase : blue, Earth : green (9.2) S-phase : yellow, N-phase : black (10) Wiring (10.1) For control wiring PVC ducts shall be used and shall be clean, be attached with compression type terminals, and shall use marking caps with signals, be easily maintainable and controllable. More than CV 3.5㎟ shall be used for control circuit. CCV cable of 2.0㎟ and up although for CT, cable 5.5㎟ and up.
- 116 - (10.2) Each terminal shall have confirmation mark. every connection between panel and apparatus shall be made within terminal block. (10.3) Cables shall be connected or cut off at terminals. At each terminal more than 3 lead line shall not be connected. (10.4) At cable terminals, bands printed with wire markings shall be firmly attached.
16.4.1.5 Rating
(1) Automatic shut off switch(ASS) at break down sections (1.1) Rated voltage : 25.8 KV (1.2) Rated current : 200A (1.3) Rated shut off current : 900A (1.4) Shock withstand voltage : 150KV(1.2 × 50us) (1.5) Operation method : Electric motor-operated (2) Power fuse(PF) (2.1) Type : In-door line disconnecting type, 1P, discharging type (2.2) Rated voltage : 24KV (2.3) Rated current : 200AF (2.4) Rated interrupting current : Sym : 2.5KV, Asym :20KV (2.5) Parts : fuse, mufflers to be attached (3) Vacuum circuit breaker(VCB) (3.1) Type : drawout type, 3 pole, singe throw type (3.2) Rated interrupting time : 3HZ (3.3) Throw type : Motor-spring type (3.4) Trip type : shunt trip (3.5) Installment method : drawout (3.6) Insulation grade : BIL 150KV(25.8KV class) (3.7) Parts : All necessary parts shall be furnished including the following. Auxiliary switch, surge absorber, manual type trip device for operation counter, drawout handle for breaker, operation counter. (4) Transformer(TR) (4.1) Type : MOLD, 3 φ
- 117 - (4.2) Primary voltage : See diagram (4.3) Secondary voltage : See diagram (4.4) Capacity : See diagram (4.5) % impedance : about 6% (4.6) Insulation grade : (impulse withstand voltage) 125KV - 22.9KV class (4.7) Standards accessory one set. (5) Change-over switch (COS) (5.1) Type : Indoor single throw type (5.2) Rated voltage : 25KV (5.3) Rated current : 200AF (5.4) Voltage withstand (BIL) : 125KV(1.2 × 50us) (6) Vacuum electronic connector(VC) (6.1) Type : 4pole single throw type (6.2) Rated voltage : 3.6KV (6.3) Rated current : 400A (6.4) Short circuit interrupting current : 4KA (6.5) Type : drawout type(combination type) (6.6) Operating type : 2a2b (6.7) Aux, contact : (6.8) Accessories : VS reactor surge control apparatus (7) Air circuit breaker(ACB) (7.1) Type : 4 pole single throw type (7.2) Rated voltage : 600V (7.3) Rated interrupting time : under 0.03 second (7.4) Throw type : Electronic (7.5) Installment method: Drawout type (7.6) Accessories : All necessary accessories shall be supplied including the following. Auxiliary switches, manual trip apparatus, operation counter built-in overload protection device. (8) Moulded Case Circuit breaker(MCCB) Circuit breakers shall have appropriate time delay mechanism when overloaded and
- 118 - shall have capacity for instantly interrupting short circuit and shall be installed safely within main circuits. Auxiliary contact and automatic trip alarm system shall also be provided. (8.1) MCCB 3P, 50AF: more than 5KV(460V) interrupting capacity (8.2) MCCB 3P, 100AF : more than 10KV‥‥ interrupting capacity (8.3) MCCB 3P, 225AF : more than 10KV 14KV interrupting capacity (8.4) MCCB 3P, 400AF : more than 10KV 30KV interrupting capacity (8.5) MCCB 3P, 600AF : more than 10KV 42KV interrupting capacity (9) Lightning Arrester(LA) (9.1) Type : Indoor type (9.2) Rated voltage : 18KV (9.3) Nominal discharge current : 2.5KV (9.4) Accessories : Supplementary parts shall be furnished in case other parts may experience troubles due to degradation or break down of apparatus element. (10) PT(Potential Transformer) (10.1) Tyre : Indoor mold type (10.2) Rated voltage : as per diagram's description (10.3) Number of phase : Single or 3 phase and up (10.4) Rated burden : To be decided based on each circuit's burden (10.5) Accuracy : 1.0 class (10.6) Accessories : Fuse and other necessaries (11) CT(Current Transformer) (11.1) Type : Indoor mold type (11.2) Rated current : To be decided based on each circuit's current (11.3) Rated voltage : To be decided based on diagram's description (11.4) Rated burden : To be decided on each circuit burden (11.5) Accuracy : 1.0 class (11.6) Over current : to select bigger value than circuit's rated interrupting current. (12) ZCT(Zero Current Transformer) (12.1) Tyre : Indoor mold type(Cable winding or split type)
- 119 - (12.2) Zero current transf. ratio : Rated 200:1.5 mA (12.3) Load : 10Ω and up (13) LV Electrostatic condenser(SC) (13.1) Type : Indoor sealed type (13.2) Number of phase : 3 phase and up (13.3) Insulation grade : BIL 2.5 KV (13.4) Accessories : All indispensables to be include (14) Instruments (14.1) Indicating (14.1.1) Type : Wide angle scale recessed type (14.1.2) Rated voltage : 150V, 300V, 380V (14.1.3) Rated current : 5A or 1A (14.1.4) Accuracy : 1.5(1.0 class for frequency meter) (14.1.5) Metering scale : For all meters following scales shall be applied (14.1.6) AC voltmeter : Apply 150% of rated voltage or as per diagram's descriptions. (14.1.7) AC amperemeter : Extended section of amperemeters shall be red-colored when it is necessary to stop primary rated scale of CT. For measurement of electric motor current scale should be extended up to 300% considering starting current. (14.1.8) Amperemeter : PT voltage transf. ratio × CT current transf. ratio (14.1.9) Frequency meter : Pointer type (14.2) Power watt hour meter (14.2.1) Type : Recess type (14.2.2)· Rated voltage : 110V (14.2.3) Rated current : 5A (14.2.4) Multiplying Ratio : Suitable to circuit's voltage transf. ratio. (15) Aux. relay meter and aux. relay (15.1) Current relay (15.1.1) Type : Induction, or static type equipped with time delay and indicator drawout type.
- 120 - (15.1.2) Number of phase : one phase (15.1.3) Rated current : 5A (15.2) Voltage relay (15.2.1) Type : Static induction or drawout type equiped with an indicator. (15.2.2) Number of phase : one phase (15.2.3) Rated voltage : 100V or 190V (15.3) Power relay : Power relay operates based on two factors : current and voltage. (15.3.1) Type : Induction or static type equipped with an indicator, which has built-in time delay mechanism drawout type. (15.3.2) Rated current : 5A (15.3.3) Rated voltage : 110V (15.4) Aux. relay : This shall be of plug-in type and shall be housed in plastic cases. (15.5) Control switch : This shall be of twist, push-button or pullout switch type. Contacts shall be of metal of high conductivity, abrasive proof and arc-resistant. (15.6) Indicating and signal lamps : Indicating and signal lamps shall be designed so as to be replaced easily at the panel fronts. Lamps shall be of circular or polygonal type of poly plastic or glass. (15.7) Trouble indicator : In front of the indicator, acrylic acid resin or glass window holes shall be provided. Black figures or letters shall be engraved on the window opening showing types of trouble. Window openings shall be easily detachable for replacement of indicating items or electric bulbs. (15.8) Target type trouble indicator : Troubles are indicated on separate target basis. The indicator shall be composed of operation coil, show-window hole, return element and push buttons. (15.9) Testing terminals are to be installed on the secondary side of very high voltage CT and PT. (15.10) Terminal block (15.10.1) Terminal blocks shall be of plastic mold type or of higher quality. Separating partition shall be installed between terminals. (15.10.2) 10% or more of the total number of control terminals shall be provided for
- 121 - backup. (15.10.3) Bases of terminals shall be separately installed each for inside wiring and incoming and outgoing wire from it. (15.11) Fuse : For panels and electric equipment, cartridge or plug type fuse and its or limiting current fuse shall be furnished.
16.4.2 Floodlight (for tunnel)
(1) Particulars (1.1) Rated capacity : 220V, high power natrium lamp 250W (1.2) Type : Diamond shaped high ceiling fixture (1.3) Outer shape : See diagram (2) Structure (2.1) Diamond shaped reflection face : This is a diffusion type polyhedrons of high quality aluminum(99% and up), hydraulically die casted by special mold. It has 3 and 4 layered, curbed reflection surface with little loss of light quantity. It shall be very sophisticatedly made without any twist or un-evenness on the reflecting face. This reflector electrolytically polished, and treated at the inner surface shall have no distortion or change of quality after long time use. (2.2) The holder shall be of ceramic and be stable for higher temperature and shall maintain a suitable insulation space to resist high voltage. The socket shall have built in contractable mechanism, so that bulbs shall not fall down by vibration. (2.3) Lamp holder's housing : The housing shall be of high purity aluminium casting matte and shall have even thickness. The end parts shall be of screw type enabling stabilizers to be fixed with pipes. Fixture to reflecting plate shall be not be of screw type but of built-in type and be design for easy maintenance of the reflection surface. (2.4) Stabilizer box : This shall be fabricated with 1.6 T cold-pressed steel plate after piecemeal welding. The upper and under face of the stabilizers shall be evenly machine-cut for radiation grooves. (2.5) Stabilizer : This shall be of higher power factor type, with more than 90% efficiency.
- 122 - (2.6) Painting : Outer painting shall be applied after full elimination of pollutants such as dust and humidity and anti-corrosion treated and then heat dried at high temperature.
16.4.3 Lighting tower facility
16.4.3.1 Floodlight's material and structure
(1) Bodies shall be of aluminum cast make and shall be solid and strong. (2) Reflecting surfaces shall be fabricated with 1.9 ton aluminum. (3) Covers shall be of heat resistant and shall use tempered glass 3.0 T and up. (4) Socket shall be of E-39 ceramic spring moulded and be trouble free for high pressure natrium lamp use. (5) Mounting bracket shall be erected on fixed base so that floodlight device could be operated at the angle more than H 30° and V 60° (6) Mounting bracket arm shall be of steel 3.0 T and up and shall not be twisted by the floodlight's own weight. (7) Packing shall be of special heat resistant rubber make and shall resisted high temperature for a long time. (8) Painting shall be applied more than once for anti-corrosion and more than twice for designated colors and then must be heat dried.
16.4.3.2 Pole
(1) Flange and supports - Shall use KAD 3503, End class(SS41) or equivalent. (2) Bolt and nut : KSB 1002 for bolt and 1012for nut
16.4.3.3 Manufacturing and fabrication
(1) Cutting (1.1) Cross sections of cut material shall be even and the surface shall be treated clean. (1.2) For flange cutting automatic cutting device shall be used and for supports, shutting device.
- 123 - (2) Welding (2.1) Lighting towers shall not be welded continuously in horizontal direction. (2.2) Bodies and flanges or supports shall be firmly fixed each other by welding among themselves. (2.3) Connecting points shall be continuously welded by CO2 welding. Endeavor to reduce welding points to prevent strength deterioration. (3) Outer shape (3.1) Fixture rings for stabilizer shall be attached to within the fixture openings. (3.2) Painting shall be applied once for wash primer and more than twice for designated color, after adjustment and full cleaning of the surface face. (4) Specifications (4.1) Floodlight tower : 10M, circular type (4.2) Accessories (4.2.1) Lightning rod - l4φ × 320L (4.2.2) Anchor bolt - 32φ × 400L (4.3) Floodlight bulb : High voltage natrium bulb 1000w × 3set (4.4) Stabilizer : 3set
16.4.4 Inspection and test after completion of work
The Contractor shall perform after completion of work test examination and inspection for each operation and others under presence of the Supervisor. Any test or inspection required by authorities concerned and by KEC shall be satisfied. Overall efficiency of every instrument and equipment shall be 90% and up.
16.4.5 Others
For other matters not specified on design drawings and documents the Contractor shall follow the instructions on the part of the Supervisor's if any.
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