Republic of the Philippines DEPARTMENT OF PUBLIC WORKS AND HIGHWAYS DAVAO DEL SUR DISTRICT OFFICE REGIONAL OFFICE XI Digos City, Davao del Sur

TERMS OF REFERENCE

I. PROJECT DESCRIPTION AND PURPOSE

A. Geotechnica! Exploration Suruey for the following:

Project Name Borehole

CLUSTER VI

Construction of Concrete Revetment along Pilan Section, Sta. Cruz, Davao 4 Boreholes; 20m depth del Sur Construction of Concrete Revetment along Tres de Mayo Section, Digos 5 Boreholes; 20m depth City, Davao del Sur

B. Duration 45 Calendar Days

II. SCOPE OF WORK

The Consultant shall provide all the labor, instrument/equipment materials and supplies, vehicles, bunkhouses, etc., necessary to perform satisfactorily the sub-surface exploration herein required, viz:.

A. Field Works B. Laboratory Testing C. Investigation and Preparation of Report D. Geotechnical Evaluation Report

The Consultant shall be held solely responsible for the result of this /drilling exploration and other activities under this Terms of Reference. rrr. DETATLED EXPLORATTON REQUTREMENTS/SPECTFTCATTONS

A. FIELD WORKS

1. Borehole Location

Borings or test pits are to be conducted at the proposed reataining wall, slope protection works or culveft location, or as close as possible if there are obstruction that cannot be removed. The location coordinates shall be recorded to 0.1 m accuracy (x,y,z) by Global Positioning System (GPS) device.

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A minimum of one boring should be performed for each slope. For cuts more than 60 m in length, the spacing between borings along the length of the cut should generally be between 60 and 120m.

At critical locations and high cuts, provide a minimum of two borings in the transverse direction to define the existing geological conditions for stability analyses. For an active slide, place at least one boring upslope of the sliding area.

2. Borehole Depth

Extend borings to depth below final ground line between 0.75 and 1.5 times the heigth of the wall. Where stratification indicates possible deep stability or settlement problem, boring should extend three (3) successesive SPT N values >30 are obtained.

Extend borings a minimum depth equal to twice the height unless a bearing layer (dense soil or rock formation) is encountered above this depth.

3. Procedure a. Deep drilling with Standard Penetration Test (SPT) shall be conducted at 7.30 meter from centerline of existing bridge left and right at each abutment. Minimum depth shall be determined based on confirmation of hard strata or bed rock . Drilling can be stopped after three (3) meters minimum penetration into hard strata or bed rock.

b. The Consultant shall perform analysis and testing on disturbed and undisturbed soil samples. These analyses and testing shall be performed in accordance with AASHTO and ASTM standards.

c. The soil samples for design shall be tested for the determination of the main characteristics (grain size distribution and classification, moisture content, , etc.)

d. Submit design recommendations, foundation condition scheme, and settlement, groundwater table, hydrological influences, excavation stability, seismic design consideration and liquefaction potentia!

e. Geological structure, especially active faults which might traverse the area, should be delineated and potential mass movement areas should be identified. Analysis for liquefaction potential during and consolidation due to soft ground should be included.

4. Handling and Core Samples

The contractor shall provide all the materials, equipment and labor necessary for preseruing samples.

B. LABORATORY TESTING

The preparation of samples for testing shall be made in accordance with AASHTO. The following tests shall be conducted but are not limited to:

2 a. Standard penetration test (SPT) at maximum interual of 1.5 m at every change in soil stratum

b. Laboratory Tests

1 Visual Identification of Soil 2 Index Properties 2.1 Moisture Content 2.2 Specific Gravity 2.3 2.4 Analysis 2.5 Atterberq Limits 2.6 3 Moisture-DensiW Relation 4 (CBR) 5 Strength Tests 5.1 Triaxial Tert 5.2 6 Consolidation Test (if soft are encountered) 6.1 On e- Di m en si on a I Co nsol i da tio n 6.2 Swell-Potential of Clays 6.3 Collapse Potential of Soils

C. SOIL INVESTIGATION AND PREPARATION OF REPORT

The soil investigation Report must be done by a Registered Civi! Engineer who have acquired experience in the field of . MS or Doctorate Degree is an advantage. The evaluation of key personnel should be rated as B0o/o is given for the relevant bachelor's degree (BS Civil Engineering), while 10olo and 5o/o for the relevant Master's and Doctorate Degree respectively (MS in Civil Engineering, MSCE major in Geotechnical Engineering and Doctor of Civil Engineering major in Civil Engineering).

KEY PERSON NEL QUALIFICATIONS

Position Qualification Person- Months . Must have at least ten (10) years experience in carrying out Geotechnical/Soil Investigation and or Surueys, Test Borings, Sampling and Analysis of similar and/or related projects. 1 Team Team . Must be a Registered Civil Engineer Leader-1.5 Leader . Must have a Bachelor's Degree in Civil Month Engineering. MS or Doctorate degree is an advantage. . Must have at least five (5) years experience in carrying out sampling and analysis for Geotechnical/Soil Investigation and or Surveys, Test Borings 1 Lab Tech- Laboratory . Must be a Registered Civil Engineer 1 Month Technician

3 . Must have a Bachelor's Degree in Civil Engineering. MS or Doctorate degree is an advantage.

KEY STAFF SCHEDULE

P0sm0N 45 C.D,

eam Leader

Labomtory Techntnn I

Detailed Tasks and Responsibilities of Key Personnel

A. Team Leader

1. Overall guidance, direction, superyision and coordination of members of the Team.

2. Collection and evaluation of geological information on the project sites.

3. Study and determination of items and method of soil investigation and laboratory test.

4. Perform necessary investigations on representative sections of the with samples to be taken at suitable intervals.

5. Investigate the physical properties of materials to facilitate the design of structures.

B. Laboratory Technician

1. Investigate the physical properties of materials to facilitate the design of structures.

2. Assists the Team Leader in the collection of necessary data and information, in carrying out detailed soil investigations.

D. REPORTS AND DELIVERABLES

The Consultant shall prepare the following reports and deliverables: 1. Inception Repoft

The Consultant is required to submit one (1) week after commencement of services. It shall outline a detailed work program and briefly describe the

4 methodology and project schedule (GANTT and S-Curue) proposed to meet the terms of reference. The report shall include the initia! findings as as preliminary layout of the forms to be used for various investigations and calculations. Inception Reports shall be submitted in soft-bound copy with title of the report written at the spine.

2. Final Repoft

The Contractor shall prepare the geotechnical report and analysis in three (3) bound copies in a form and substance to be submitted to DPWH, Davao del Sur District Engineering Office, Digos City, Davao del Sur within Foty Five (45) calendar days upon receipt of the Notice to Proceed. The final report shall not be limited to the following:

a. Field Investigation and Methodology b. Borehole Drilling and Sampling c. Laboratory Testing d. Final Boring Logs (BL) e. Final Laboratory Tests Results (FLTR) f. Borehole Location Plan g. Soil Profile along structures showing boring/drilling logs h. Investigation Repoft i. Soil Bearing Capacity j. Recommendation if called for such as type of measure/structure of work rV. OTHER DATA TO BE SUBMITTED

A. Boring Logs

1. Job, boring, hole number, date, time, boring/drilling, foreman, superuisor 2. Weather condition 3. Depth of boring at start of day 4. level in casing at start of day 5. Method of penetration and flushing system 6. Description of soil strata encountered 7. Depth of soil boundaries B. Size, type and depth of samples and sample number 9. Type and depth of in-situ tests 10. Standard Penetration Tests Resistance, "N" Value 11. Recovery ratios of samples 12. Detailed notes on boring/drilling procedure, casing sizes and resistance to driving, description of wash water or spoi! from boring/drilling tools 13. Depth of boring at end of day 14. Other relevant information such RQD, percent core recovery, angle of etc.

B. Photographs

Photographs showing the borehole drilling and sampling at each proposed sites shall be taken by the Contractor and incorporated in the report. Photographs shall be taken at each borehole location depicting the following:

5 1. Equipment used 2. Core drilling operation 3. Water level measurements 4. Performance of SPT and Shelby tube sampling 5. All cores in the core boxes, SPT and Shelby tube samples 6. Date photographs was taken

V. WORK SCHEDULE

Detailed Time Schedule

DESCRIPTION 45 C.D. Mobil2atbn/De mobilizat b n I I

Drilling

Laboratory Testing

Geotechntal Evaluation Report pre paratbn

The Consultant's contract period for undertaking the sub-surface exploration works including laboratory tests shall be Forty Five (45) calendar days and the Consultant shall commence work after receipt of Notice to Proceed.

Prepared by: Approved:

M.M o, JR. LANDO R. OROC OIC.C Planning & Design Section BAC Chairperson

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