Metro Line 4 in Rio De Janeiro

16 Brazil Tunnel 6/2012

Trace of Metro Line 4 of Rio de Janeiro

Metro Line 4 in Rio de Janeiro

2012 kicks off a 4 year marathon for Rio, beginning with the Rio+20 Summit traffic on major avenues in Rio. on the environment, and running the ’14 World Cup and the ’16 Summer Crossings that in times of heavy traffic can last up to 2 hours by Olympics. The following article shows, how tunnelling helps to prepare the car will be shortened to 30 mi- infrastructure in Rio de Janeiro. nutes using the metro. The activities for the imple- Pedro Nobrega, Planning and Projects engineer, the subway access necessity mentation of Line 4 began in Constructor Consortium Rio Barra – Metro Line 4, Rio de Janeiro / Brazil even more essential. Due to March 2010 and since then the [email protected] the multiplicity of geological excavations are being executed features, several engineering one step ahead of 4.5 m per There is no question this is the further the preservation of the works are being held, such as day, yet in rocky areas. There are most prosperous moment that citie‘s environment that boasts bridges, hillsides retaining walls 5 companies that form the Con- Rio de Janeiro experiences sin- the largest urban forest in the and tunnels mainly using NATM sortium Builder Rio Barra (CCRB), ce the days when still housed world, projects and plans have methodology for rocky stret- which now has the participation significant political decisions as been developed to expand its ches and cut and cover and of 1,600 employees, and fore- the Brazilian capital. While the metro network. Nowadays, the TBM for sandy soils (Fig. 1). casts to reach 2,500 employees government injects reais into the subway system of the city has The new line is located at the between production and admi- economy and announces new 40.9 km in length split into 2 south and west portion of the nistration. investments in infrastructure and lines, Line 1 and Line 2. At the city, the second being the regi- For the extension of 9 km housing, the „carioca” populati- outbreak of the current subway on with the largest population stretches out the route that on, name given to those born in plan is the creation of the Metro growth in the last decade. At the includes the stations of Jardim the city, grows and develops by Line 4 of Rio de Janeiro. end, it connects to the existing Oceanico, São Conrado and the limits of Rio, up today to 11.7 The Line 4, scheduled to Line 1, which caters primarily to Gávea. Due to the presence of million people. start operating in 2016, ex- the neighbourhoods located in rock in its entirety, this section is Still, just as all great world tends for 16 km through rock the center and north of the city. excavated through the drill and metropolis, the city suffers from masses, canals and ocean regi- At the year of inauguration are blast method. Currently there are severe traffic issues. Due to ons. The peculiarity of the local predicted 425,000 passengers 3 digging fronts to obtain advan- the necessity of vehicle traffic geography limits the options daily utilizing the services of Line ces, 1 at the beginning of the reduction in roads, and taking for road access to the different 4, and nearly 950,000 passengers path and 2 at the intermediate advantage of favorable geo- neighbourhoods where the in the total of the 3 lines, thereby portion, located at São Conrado logical conditions, in order to line is stretched, thus making bringing a huge relief for vehicle station, where 2 fronts in oppo- Tunnel 6/2012 Metro Line 4 in Rio de Janeiro 17

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Excavation excerpt in Barra da Tijuca and the beginning of bitunnel Front drilling

site directions where started. interconnections between the provements of techniques and cycle counts with the use of ex- The entire length of the tunnel tunnels, optimizing the place- procedures have been constant, cavators, loaders and lifters that will be excavated in November ment and execution of the same so that productivity and safety through an efficient and alig- 2013, accounting for a total of 41 tunnels. These solutions allowed are in increasing trend. Current- ned logistics system takes turns months of excavations. the project to follow the NFPA ly, the first line of excavation is at the excavation front seeking There are several sections of 130, an international standard advancing with almost 2 km. lower production downtime. excavation that goes from 33 m² used in the evacuation of large At the end of the initial 682 m In total, there are 9 excavators, and reaches 368 m² at the São tunnels in case of operational excavated as a session of up to 6 loaders to transport material Conrado station which will have accident (Fig. 2). 122 m², the tunnel splits into the and 8 lifters which are used for its total length of 179 m excava- 2 single tubes of 33 m². the implementation of shotcre- ted in solid rock. The slimmer ses- Excavation cycle Usually there are 2 daily de- te, placement of rods and other sions are due to a choice for a pro- During the investigations 152 tonations, and they occur in the ancillary services such as exten- ject that includes 2 single-track drillings were performed, inclu- interval between the steps of the sions of networks of utilities and tunnels, known as twin tunnels. ding a modern method of te- cycle, that begins with clearance ventilation ducts. Surveys were performed seeking levising the layers of holes. The of demolished material and ends It is during loading and blas- the most viable solution, meeting technique is based on achieving up at the explosives loading for ting that security becomes even international standards for secu- color images of the walls of holes, detonation. For drilling, the con- more necessary. In addition to the rity. It was presented as a viable both above and below the water sortium has 7 drilling machines ventilation system, with jet fans option, the construction of 2 par- level, which properly processed (jumbos) with spears range of and 1.800 mm diameter duct allel tunnels, whose sectional ex- allows viewing, editing and ana- 4.5 m. On average 2.5 hours are along each single tunnel, the tun- cavated area is notably the same lyzing the images in a practical required for execution of the 71 nels also feature signalling, unique as a double track tunnel, with the way. Through this practice, it holes, 13 of them at the center passages for pedestrians and sa- advantage, instead of outputs to was possible to analyze cracks, pilot, and the rest is spread over fety staff during the 24 hours of the outer surface, the passage discontinuities, faults, and other the typical session of 33 m². For services divided into 3 shifts. through galleries for the tunnel geomorphological features. In detonations, cartridge emulsion, adjacent track. The cross passages addition, seismic surveys were silent lines and fuses are used Geological fault of between the single tunnels every performed (electrical profiling) (Fig. 3). Soriman 244 m fits the bill as one of the in areas where its geological Through the perforation of 4 Geomorphological changes are safest in the world in this regard. complexity and fragility de- m, obtains the average of 3.70 observed and studied each ad- In addition to aggregate solution, manded further investigations. m advance counting thus 124 vance. In addition to challenging, the auxiliary facilities required to After the completion of studies m³ of disassembled rock which is it increases the risk of schedule supply the energy system over on 2 August 2010 the first blast then transported for disposal in and cost variation. Results of the the tunnels, was designed in to advance the excavation was place approved by environmen- surveys identified a stretch of the an integrated manner with the performed. Since then, the im- tal authorities. Furthermore, the tunnel passage in which a geolo- 18 Brazil Tunnel 6/2012

gical discontinuity with the pre- In June 2011, after comple- pulleys, and the traction is made 27 metal crankshafts in additi- sence of water could affect the tion of the service tunnel exca- by the machine translation on on to shotcrete. The geological pace of excavations. Due to the vations, began the process of rails. After slicing the total rec- investigations that were held at lack of geomechanics quality, as opening the mouth of the tun- tangle arc section with 15.30 m the location indicated an initial a function of increased frequency nel on its starting point in Bar- wide and 7.88 m high, it was ne- stretch with only 3 m in length, of subvertical joints cutting across ra da Tijuca, but as the service cessary to use a hydraulic breaker to be dug in soil and saprolite the tunnel, and locally filling frac- tunnel was already completed, to open the section and further rock alteration, entering below tures with solid carbonate or Kao- this time the direction of the ex- transportation of excavated ma- the crystalline rock mass on the linite with the presence of water, cavations would be inside the terial (Fig. 5). horizon dominated by facoidal all necessary measures were ta- tunnel out. Due to the proximi- gneiss that occurs in the massive ken to ensure safety. ty of buildings, which limits the São Conrado excava- rock formations near the coastal The decision taken for cau- use of explosives to demolitions tions region of Rio de Janeiro. tious measures includes: ad- and also because of its format of Following the excavation of the These initial excavations were vance of 1.5 m per detonation, a big vertical wall of solid rock Tunnel, began excavations at carried out mechanically, followed crankshafts spaced at 0.80 m with no soil, it was opted for the the second service tunnel, loca- by rock excavation developed each, rods placement with 4 to methodology of cutting with ted on the rocky hillside of São by applying techniques called 5 m in length plus steel frames diamond wire. Conrado, with the sectional area “cold disassemble”, with hydrau- and pre-grouting. To combat the The process comprises a steel of approx. 90.80 m², from which lic breakers and also small flares water column of approx. 40 m wire with cutting rings (beads or followed the excavations for the with explosives, that are required it was used a 500 mm layer of diamonds) separated by regu- underground station of the same to conform and upright the front shotcrete in addition of water- larly spaced segments of special name and also enabled the cre- of rock excavation itself (Fig. 6). proofing membrane. Despite the plastics or springs. These wires ation of 2 new digging fronts in After excavation of approx. decrease in the rate of excavati- are driven machines that makes opposite directions. 10 m, gate of steel and concrete on of approx. 75 %, the dreaded arthritis with the rock at the same At the mouth of the service was installed, completely closing 247 m have been successfully time is pulled towards the desired tunnel it was completed the the mouth of the new tunnel to overcome, and in no time “yel- cut, producing the cut. The move- first stage of treatments and it be excavated. Its function would low light was lit“ (Fig. 4). ment of the wire is made by the was also built a fake tunnel with then be to attenuate noise in addition to protection due to the 4 positioning of the detonations, nearby a street with large move- ment of people and vehicles, and its forward position to inhabited buildings, offices and commerce in general. These auxiliary structures, allowed the start and continua- tion of the excavations, with the systematic use of explosives, but with more rigorous safety procedures, diverse instrumentation of tunnel and hillside, and more accurate fire plans. The rock mass on the slope where the tunnel is being excavated features geological and geomechanical adverse conditions in their upper bounds. At some points, instability situ- ations are revealed, evidenced by torrential rains that occurred in April 2010, before the start of work on implementation of Line Execution of services in the region of the Soriman fault 4. During this event there was Tunnel 6/2012 Metro Line 4 in Rio de Janeiro 19

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Opening of the tunnel mouth in Barra da Tijuca São Conrado site slippage of part of the colluvi- its route, the tunnel crosses be- because of projects to opening being made. Furthermore, benef- al layer deposited on the rocky neath one of the leading and of Reboucas and Two Brothers actors were carried out such as mass. Although no casualties oldest slums of Rio de Janeiro tunnels, which contributed to the revitalization of parks and the have been originated, the event (Fig. 7). a greater availability of employ- reform of the Rocinha’s residents caused several damages to the Rocinha, as is renowned, ment in the region. Nowadays association. These actions have region, including the destruction currently has a population of these inlined highway tunnels promoted the harmonization of homes and obstruction of pu- approx. 70,000 inhabitants over are part of the main access route with the communities where the blic roads. an area of 1.43 km². Located at a to the west side suburbs. work is located, facilitating the Given the presented scenario, large area of hillside and valleys, The constant migration mo- implementation of services. As an extensive project of conten- had its occupation process star- vements into Rocinha, have a consequence of heavy rains in tion was prepared for the hilly ted in 1940 by people who be- made it massively populated, mid-2010 landslides occurred in area, including several types of lieved to be public those lands, a fact which resulted in several the region of Rocinha, a warning rods, coatings with shotcrete, i.e. without owner. problems for the region. Due to was generated for the risk and and the construction of contai- From the 1950s, there was a the uncontrolled occupation the possibility of disasters within ning walls. So far 736 root piles migration rise of people from the and the lack of an urban plan, the region. Under this scenario, have been implemented, divided Brazilian Northeast to Rio de Ja- the buildings in the area have studies have been conducted into 17 retaining walls along the neiro in pursuit of employment serious structural problems. through the Geotechnics Insti- hillside. Thus, the geographical and better living standards by di- Buildings of up to 8 floors were tute of Rio de Janeiro - GEO-Rio, position, the geomechanical and recting in part to Rocinha. During built, away from supervision involving drilling, topography geological conditions of the São the 1960s and 1970s, there was and approval of the responsible and structural analysis of buil- Conrado site area caused man- a new surge of population, now agencies. The space is constantly dings that led a mapping of local datory practices of security pro- changing due to the action of risk (Fig. 8). cedures for the excavation with 7 the residents who builds homes By these studies it was identi- explosives. without first consulting technical fied a critical area through which experts, offering an imminent the tunnel is being dug, which The “Favela” Rocinha risk for the entire community. generated several actions that It is well known in the communi- In order to establish a close involves from the concern for the ty of tunnels, that underground communication with the com- welfare of the community up to construction in urban environ- munity, the Consortium provides procedures for the fire plan. The ments poses eminent risks to several channels of contact. Pre- passage at issue, of approx. 200 buildings and avenues during liminary inspection on the buil- m, features difficulties because its excavation. This risk is even dings, registrations, meetings it is a region where the cover- more enhanced in the case of and periodic visits and commu- age over the tunnel is very thick the construction of Metro Line nications reporting on the execu- in some locations reaching 15 4 of the Rio de Janeiro. Along Favela Rocinha tion of services are continuously m of colluvium soil, and 8 m of 20 Brazil Tunnel 6/2012

rock highly fractured, altered and not very coherent, evidenced 8 through survey testimonials recovery. Adds up to this fact, the constant contamination of the ground in the slum area, mostly due to lack of sewage system, which contributes straight to the physical and chemical alteration of soil and rocks, causing loss of quality (Fig. 9). Given the challenges, many procedures are being adopted. As an example, the instrumentation of the region with the participation of a team which Sliding zones mapping at Rocinha monitors the area through repression pins, tassometers, pie- and fire plan to return to the The blasting for advancement in cycles and must constantly be zometers and seismometers that safety limit above. The value of a 184 m² section partialized in at least 8 m apart. This definition are used at the moment of the 128 dBl must be adopted as a upper and lower part (bench). accords to the requirement to detonations. 50 homes located limit of air impact. This measure There are several reasons for protect the sides of the tunnel in areas of influence of the works seeks to reduce the physical and choosing this methodology, section, once the complete de- are receiving repression pins and psychological effects of blasting among then there is the lowest tonation section would lead to are being daily monitored. The on the community, knowing that use of explosives by detonation vulnerability to collapse the tun- analysis considers horizontal and such limits exempt impacts to due to the necessity of noise nel walls. Therefore, when per- vertical displacements of the the environment and living and vibration mitigation and forming the detonation of a side pins and are provided in real- creature. However, up to now, the limitation of the perforation there is the possibility to perform time for the designers, so they displacements or vibrations ex- machines (jumbos). there, the necessary treatment can carry out specific modifica- ceeding the limits set out have The partialization of advan- for protection and accommoda- tions in advance of excavation not been captured as a function cement of the section is perfor- tion of the mass thus releasing activities. of high safety and conservatives med so that the advance at the the advance opposite portion. In order to assess the vibra- actions. top of the tunnel face is always Furthermore, the following de- tions triggered by blasting, seis- ahead of the lower section of the tonation of a lower part side, mographs with geophones are São Conrado fire plan bench. Furthermore, the bench allows the assembly of a ramp being used. Prior to each blast 4 Currently, the advance of the is divided into right and left, each of the material itself on the op- reading points are maintained tunnel in São Conrado is in the with 40 m². According to the de- posite flank disassembled, thus on the nearest residential buil- vicinity of where the risks related signers, the sides of the bench allowing access to the execution dings, usually fixed to the pillars. to the surface shows the highest. must be detonated in different of services on the upper level, Such locations refer to points on which is already advanced. the surface which are located The partialization of the tun- closest the front of the exca- nel section occurs in 3 stages, vation. For the present stage, it at the first step, the face of the was determined that it should dome suffers the drilling of 228 limit the velocity of vibration that uniform holes. The dismantling can hit the inhabited areas of Ro- of the shell volume of approx. cinha and risky sliding areas by 421 m³ requires the amount of 4.2 mm/s in the resulting. If this 950 kg of explosive, resulting value is exceeded for 3 conse- in a charge ratio of 2.25 kg/m³. cutive captures to a maximum The detonation of the center of 6 mm/s, or if a single abstrac- pilot area, equivalent to approx. tion exceeds 6 mm/s, it will be 9 1.20 m2, where the highest necessary to act following the concentration of loading blast excavation sequence, advance Geological zones risk of sliding along the length of the tunnel occurs milliseconds before the Tunnel 6/2012 Metro Line 4 in Rio de Janeiro Elektrotechnische Infrastruktur für Strassen rest, providing relief of tension Conclusion und Tunnel that facilitates the targeting se- The construction of Metro Line quence of rock takedowns. Each 4 that connects West and South of the 46 holes that defines the Zone is in fact an essential work contour of the section receives a running in the city of Rio de Ja- loading of a cartridge emulsion neiro, not only because of its im- of 0.532 kg of ammonium nitrate portance to the improvement of and another of the same weight mass transportation for the 2016 in the middle. To smooth the cut- Olympics, but also for what rep- ting edge, avoiding over breaks, resents as a legacy to the urban it is applied a NP40 line (40 g/m planning of the city. During its

NH4NO3) along the depth of the development the work causes hole. This method was chosen interventions in traffic and the over the method commonly cal- daily routine of the population, led “barbecue”, which was initially which becomes conscious in used and consists in the inserti- favour of the improvements for on in the hole of a bamboo cut the city itself. On the other hand, lengthwise and loaded with less the building Consortium, seeks effective cartridge emulsions. to mitigate the impacts of work However, this method generates in Rio by generating a series of more irregular cuts, sometimes environmental actions that add causing rework and inaccurate value to the city. Among these rock cuttings. actions are the transplantation For detonation of the bench, of a bromeliad area, recovery of Fordern Sie uns fewer explosives are used, since public facilities, in addition to the the free face above the area to recycling of 120 t of metal, 9 t of bei der Automatisierung von be advanced is no longer confi- paper and reuse of 50 million l of Gewerken inner- und ausserhalb ned, requiring only what it is the water used for the services. des Strassentunnels “rising fire”. Overall, advances in For the completion of the Die Ausrüstung von Verkehrspro- the bench area are more agile work there are still remains 4 jekten und Tunneln stellt besondere than the upper part, due to the years ahead, and up to there hohe Betriebssicherheit reduced size of section and less many challenges will be faced. Anforderungen an die elektrische need for treatment. For each de- Also planned there are the cons- Infrastruktur. Ob es sich um die tonation of the cap feed is 3.60 truction of a bridge, excavation schnelle Vernetzung aller Geräte und m, obtaining 90 % efficiency of stations in soil and rock and Systeme, die wirtschaftliche Steuerung relative to of the drill perfora- other services that require the von Pumpen, Beleuchtung und Belüf- tion. It was determined that if best engineering practices. But tung, die zuverlässige Energieverteilung there are mentioned problems the progress of work has shown related to excessive vibrations that the staff has been perfor- oder die sichere Überwachung aller in the regions bordering the ex- ming its role with commitment Schutzeinrichtungen Einrichtungen handelt - wir entwickeln cavation front, the fire plan will and perseverance so the work für jede Anforderung die optimale be modified so that the area of can be completed by 2016 and Lösung. Unsere Spezialisten wissen the cap, which has the largest this important gift delivered to genau, wovon sie sprechen. load is reduced, thus increasing the population of the city‘s ow- the area of the lower part. For ner to the world‘s most enchan- Mehr Informationen unter not being confined, the deto- ting beauty. nation of the lower portion ge- Telefon 052 354 55 55 oder nerates less vibration reaching www.phoenixcontact.ch Kommunikation the surface. These adjustments were not needed yet, since the captures of the seismographs are still far below the stipulated limits.