Archives: Projects

Ceneri Base Tunnel

Project Overview

The AlpTransit Project is a massive rail project designed to provide more efficient rail freight routes via base tunnels through the Gotthard and Ceneri mountain ranges. Currently, freight trains traveling up the mountain ranges require pushing locomotives due to steep gradients. The base tunnels will provide a route for freight trains with minimum elevation gain and will shorten passenger train times between Zurich and Milan. Some route times, such as the trip between Lugano and Bellinzona, will be cut in half with the completion of the Ceneri tunnel. The Ceneri Base tunnels and the Gotthard Base tunnels will combine to create a new rail system that will span over 70 km (43 mi) of TBM-driven tunnels and 16 years of construction. The completed rail line is expected to open to traffic in 2019.

In April 2007, Contractor Consorzio Monte Ceneri (CMC) JV – a consortium of CSC, Lugano, Frutiger SA, Thun, Rothpletz, Lienhard + Cie, and Aarau, signed a contract for a 9.7 m (31.8 ft) Robbins machine to bore a 2.4 km (1.5 mi) adit on the Ceneri Base Tunnel Project. The completed adit tunnel joins up at approximately the halfway point of the main rail tunnels. The Main Beam TBM was completely refurbished near Milan, Italy where the cutterhead diameter was changed from 7.6 m (24.9 ft) to 9.7 m (31.8 ft). The TBM was the first machine on the AlpTransit project to utilize 483 mm (19 in) cutters, designed to offer a higher cutter load and longer cutter life resulting in fewer cutter changes. The refurbished machine previously bored successfully on the main headrace tunnel of the Kárahnjúkar Hydropower Project in Iceland.

Geology and Ground Support

Rock in the area consists of schist, Swiss molasse, and Ceneri orthogneiss with a UCS of 30 to 130 MPa (4,300 to 18,800 psi). Much of the tunnel was excavated under high cover of 600 m (2,000 ft). The geology of the tunnel alignment was good for TBM boring, with no squeezing ground or large water inflows encountered. New probe drills, designed in Robbins U.S. locations, were used to verify ground conditions ahead of the TBM. Temporary tunnel support including rock bolts, ring beams and shotcrete were also used depending on geology. Excavated material was temporarily stored at a lot onsite for later preparation as rock aggregate for concrete.

Tunnel Excavation

On November 6, 2008 excavation of the adit tunnel was completed on schedule after only ten months of boring. Only 30 cutter rings were changed during the last kilometer of boring, with the cutters excavating a combined 160,000 cubic meters (5.9 million cubic feet) of hard rock. Daily advance rates averaged 18.5 m (60.7 ft) – about 61% higher than averages achieved by similar machines boring the Gotthard Base Tunnel using 432 mm (17 in) cutters.

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奥莫斯的安第斯山隧道

项目概况

奥莫斯的安第斯山隧道已经有100多年的历史了，在1950年使用钻爆技术进行了几次尝试。这条隧道全长20多公里(12英里)，是一项更大工程的一部分，该工程计划将安第斯山脉东侧的Huancabamba河的水输送到太平洋流域的干旱地区，通过一条隧道穿越大陆分水岭。第一阶段包括兴建4300米(140英尺)高的大坝，把位于圣斐利贝村附近的Huancabamba河转移到太平洋一侧的干燥的奥莫斯河上。现在，隧道工程的第一阶段正在运作，该计划每年将提供超过20亿立方米(5000亿加仑)的水用于灌溉560平方公里(13万英亩)的农田。接下来的阶段将包括至少两个钻爆隧道，两个水电站，每一个都发电600兆瓦，一个运河系统来过滤整个海岸的水。

 

地质条件和机器设计

掘进机面临的是复杂的地质条件：石英云母片岩、安山岩和凝灰岩构成的围岩、UCS（单轴抗压强度）在60至225兆帕（8700至32600 psi）之间。隧道沿线有超过400条断层线，其中两条主要断层线宽约50米(160英尺)

高覆盖层还带来了另外一个问题：隧道内的高温，预计隧道内的温度将超过54摄氏度（130华氏度）。工地高的海拔(1080米/ 3500英尺)导致空气密度较低，每立方米空气的传热能力降低为了应对这种高温环境，罗宾斯公司为这套设备设计了独特的通风和风冷系统：两套相互作用的系统用于把隧道内的温度降到32摄氏度（90华氏度）或更低。

隧道掘进

从2008年底开始，掘进机就进入了高埋深隧道段，在那里，工作人员经历了巨大的过度断裂和导管，以及超过16,000个记录的岩石爆裂事件，这些事件无法用铁丝网、岩石螺栓和环梁来控制。为了更好地控制破碎的岩石，罗宾斯和 承包商Odebrecht 通过安装一种新型的掘进机围岩支持来改变。设备的顶部被移走，取而代之的是麦纳利(McNally)围岩支护系统(见右图)。

McNally的工作原理是将弯曲的手指型钢板替换为侧弧形的钢精排储存仓。储存仓轴向从刀盘的背面延伸到刀盘的支撑。在掘进机进入冲程之前，工作人员将金属或木头的板条滑入存储仓，这样，每个储存仓里就有两排的板条。从储存仓伸出的板条的末端，用钢带固定在隧道的顶部。当机器前进时，板条从储存仓中挤压出来，然后用继续把后面的板条用螺栓固定在隧道顶部。为了防止变形和岩石的下落，隧道的长度被板条会继续重新加载使用

 

穿过断裂和破碎的岩石段的隧道也在刀盘上造成了不必要的磨损。为了解决这个问题，罗宾斯的工程师们增加了19毫米(0.75英寸)厚的磨损板和50毫米(2.0英寸)厚的方形钢，被称为“回力标”，在每一个刀具的前面。回力标从而在遇到状岩石到掌子面岩石爆裂，可以保护刀座。

掘进机的改良让设备的推进速度稳步提高，这台机器每月的进尺达674米(2211英尺)。考虑到2008年4月和2009年3月发生的两起危险的局部洪水，这一改善的速度更加引人注目。这两起洪水淹没了该地区，超过一米的泥浆，并摧毁了道路。

经过四年的奋力开挖和地质条件的挑战，掘进机于2011年12月20日到达了终点。秘鲁包括总统在内的政府官员都一起来到工地见证这一重大的隧道贯通。

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Guangzhou Metro, GuangFo Line

Project Overview

Since 2006, China has invested nearly USD $200 billion in rail infrastructure – a plan that promises to be one of the largest national railway expansions since that undertaken by the U.S. in the 19^th century. Guangzhou’s metro expansion is part of the Pearl River Delta Inter-City Rapid Rail Project and China’s first ever inter-city rail link.  The 32.2 km (20 mi) Guang-Fo line running between Guangzhou and Foshan was awarded in 12 separate lots.  The owner, Guangzhou Metro Company, chose to utilize 16 different TBMs.

Lot 12, running between Jushu, Xilang, and Hedong stations, was awarded in 2007 to the China Communication Construction Corp., 2^nd Navigation Engineering Bureau Ltd. (CCCC). The contractor, CCCC, selected two 6.3m (20.5 ft) diameter Robbins EPBMs for the parallel 2.6 km (1.6 mi) long rail tunnels. The two cutterheads began turning in January and February 2009, after being launched from the cut and cover site of Jushu station in southern Guangzhou.

Geology

The geology on the metro’s Lot 12 consisted of a complex layered profile, ranging from highly weathered to slightly weathered granite, coarse sand, and silt at pressures up to 4 bar. Around 70% of the tunneling was through a mixed face, with the alignment above the spring line in soft soils and the bottom half of the tunnel in rock of at least 50 MPa (7,250 psi) UCS. The remaining 30% consisted of flowing sand with high water content.

EPBM

Both Robbins EPBMs were designed with spoke-type cutterheads including large opening ratios of 37%, which allowed for smooth flow of muck into the mixing chamber. Both 432 mm (17 in) hard rock single disc cutters and carbide bits were used to combat the mixed ground conditions expected.

Four independent foam injection points on the cutterhead were used to further consolidate the muck flow. Foam was used on the Guangzhou tunnels because it was less costly and it also reduced the required cutterhead torque. Muck was removed using an 800 mm (31.5 inches) diameter shaft-type screw conveyor due to the fact that no large boulders were predicted. Active articulation was chosen for this project, mainly because much of the transit twists beneath the city, with curve radii as small as 200 m (656 ft).

Tunnel Excavation

The two Robbins EPBs were launched in December 2008 and January 2009 respectively. After only seven months of boring, the two machines achieved more than 16 project records including a best month of 377 m (1,235 ft) – higher than any of the 16 TBMs that have worked on the Guang-Fo Metro Project.

Surface settlement was a major concern as the tunnels run beneath rivers, research sites, roadways, and vulnerable building foundations. Back-fill grout was used to fill the gap between the 300 mm (12 in) thick, pre-cast concrete segment rings and the surrounding soil. Some of the high-risk areas included the 80 m (262 ft) wide, 4 m (13 ft) deep Huadi River between Jushu and Xilang stations, and also the Pearl River Fisheries Research Institute, which has numerous sensitive ponds used for research into high-yield fish farming.

Both machines finished a month ahead of schedule, and operated around 95% availability. As of August 2009, only 66 disc cutters had been changed on the first machine and 46 on the second, while no carbide bits had been changed on either of the TBMs. The first machine completed its initial breakthrough into the Xilang station on August 15, 2009 and its final breakthrough in September. The second machine broke through into the Xilang station in September and made its final breakthrough in October 2009. 

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Glenwood Cable Tunnel

Project Overview

EIC Associates were contracted in 2006 to construct over 13 km (8 mi) of a 115 kV power transmission line through Stamford, Darien, and Norwalk in Connecticut, USA. The final system includes three circuits consisting of 92 vaults and 62 handholds. EIC used a Robbins 1.5 m (60 in) Double Shield Rockhead (SBU-RHDS) to excavate two crossings under the Metro North Railroad in Darien, which turned out to be particularly difficult rock.

Due to the very poor ground conditions, G. Donaldson, a division of Hayward-Baker, Inc., was contracted to pre-grout utilizing two types of pre-grouting.  The two types of grouting used were: horizontal grouting to stabilize the tunnel alignment, and vertical grouting around the road and rail structures to help reduce the risk of surface settlement.

Geology

Exploratory testing of the bore area found highly fractured meta-quartz monzonite ranging from 5,000 to 20,000 psi (35 to 140 MPa) UCS with Rock Quality Designations averaging 45%. Due to the unstable ground conditions, the location of the tunnel was lowered an additional 3 m (9 ft). However, further testing found extensive fractures here as well.

Rockhead

Rockheads are best suited for longer tunnels, where line-and-grade are critical such as in gravity sewers. EIC chose to use the best available option, the Robbins Double Shield Rockhead, due to the instability of the rock as well as the length of the bore.

The 1.5 m (60 in) diameter Double Shield machine, designed specifically for the highly fractured rock, featured a breasted plate cutterhead, which consisted of a steel plate in front of the standard cutterhead with slots for the single disc cutters. Grill bars were also added across the muck chutes to limit the size of rock allowed onto the conveyor.

Tunnel Excavation

Excavation started in the spring of 2008, operating six days a week in two ten-hour shifts. The machine bored the two crossings averaging 254 to 635 mm (10 to 25 in) per hour, due to rock hardness. Using articulation cylinders and stabilizer pads, the machine was able to maintain line and grade throughout the bore. EIC elected to use reinforced concrete pipe for the lining, which was laid behind the machine using a pipe jacking system.

Throughout the bore, field service technicians adjusted the penetration rate of the machine, as pre-grouted sections made the rock face softer and easier to excavate.  This adjustment required either a decrease in thrust cylinder pressure or cutterhead speed to avoid plugging the muck removal system with too much debris.  The machine’s variable speed electric drive allowed for fine tuning throughout the drive. 

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Theun Hinboun Expansion Project

Project Overview

The Theun Hinboun Expansion Project is a hydroelectric project that requires a 5.5 km (3.4 mi) headrace tunnel bored by a Robbins Single Shield TBM – the first instance of TBM-driven tunneling in the country of Laos. Located on the banks of the Nam Theun River, the project consists of a new station, dam, and headrace tunnel which will add electricity supplies to Laos and neighboring Thailand by 2012. The USD $270 million project will address the power needs of the two countries by adding an additional 280 MW annual generating capacity.   The original plant, built by Recchi-CMC JV between 1995 and 1998, already produces 220 MW annually. Power will be shared, with approximately 220 MW going to Thailand and 60 MW to the Laotian national power company, Electricite du Laos (EDL). The project also promises to improve the supply of electricity in Laos by extending the 115 kV transmission grid to the project area and increasing power supply to the existing grid.

Single Shield TBM Design

On December 22, 2008, CMC di Ravenna signed a contract with Robbins to provide a 7.6 m (15.1 ft) diameter Single Shield TBM. The TBM was assembled at Robbins’ Solon manufacturing facility in Ohio and shipped to the jobsite along the Nam Theun River. CMC di Ravenna chose the Robbins Single Shield for its short shield length, based on the geology and the need for continuous tunnel lining.

The Robbins TBM was designed to accommodate moderate squeezing ground conditions. Ground along the tunnel alignment consisted of alternating strata of sandstone, siltstone, and mudstone. An articulating cutterhead with overcutters allowed the machine to excavate 100 mm  (4 in) beyond the nominal tunnel diameter. To support the ground and provide final lining, 280 mm (11 in) thick, pre-cast concrete segments were used in a 5+1 arrangement, making a finished tunnel diameter of 6.9 m (22.6 ft).

TBM Excavation

During excavation, the Robbins Single Shield TBM averaged 19 m (62 ft) per day, with a peak advance rate of 37 m (121 ft) in one day.  Ground conditions consisted of fair to good rock for 95% of the tunnel length, with some sections of poorer rock quality.

Challenging conditions included an anticipated 15 m (50 ft) wide fault zone at about the 4,700 m (2.9 mi) mark with flowing water.  The crew was able to drill a borehole and use expanding foam to consolidate the ground, allowing boring to continue.  The machine broke through on schedule, on November 21, 2010.

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KOPS II Hydropower Project

Project Overview

The KOPS II Hydropower project is located inside the Alps Mountains, drawing from the same reservoir as the KOPS I hydropower station, commissioned in 1969. The stations are supplied by the Rifa balancing reservoir, located between the tourist centers of Gaschurn and Partenen.  The KOPS II pump station and headrace tunnel was built to supply power to the grid during peak demand and to ensure long-term network stability. Being that KOPS II uses the same reservoirs, no additional water was needed compared to KOPS I. Also, KOPS II uses an existing high-voltage line currently used by KOPS I.

Construction began at Kops II in 2004/2005, after Swietelsky Tunnelbau GmbH, Torno SA and Torno Int. S.p.A JV signed the contract for a 5.54 m (18.0 ft) Robbins Double Shield TBM. Construction of not only the tunnel, but the entire hydropower plant, was under strict watch as an Environmental Impact Assessment (EIA) was initiated. More than 500 regulations had to be followed assuring that construction would be done in an environmentally friendly way and in a tight time frame of 42 months.

The completed KOPS II plant provides an additional 450 MW in turbine mode and pump mode to the already existing 247 MW hydropower plant.

 Geology

Geology on the tunnel alignment consisted of schist gneiss, migmatite gneiss, mica-schist, amphibolite gneiss, hornblende gneiss, granite-gneiss and aplite gneiss ranging from 30 to150 MPa (4,000 to 22,000 psi) UCS.

TBM Design and Tunnel Excavation

The Robbins TBM used 483 mm (19 in) back-loading cutters to bore through the very challenging and mixed geology. The cutterhead was designed with 9,074 kN (2,040,000 lb) of thrust and 2,159,424 N-m (1,591,300 lb-ft) of torque.  The TBM power was 1,575 kW (2,112 hp).

Boring commenced on the headrace tunnel on July 20, 2006.   The TBM was one of the first machines to use a back-loading 19 inch cutterhead. The resulting cutter blockage percentage ratio was very low—only 2% over the duration of the project, compared to the more typical rate of 10-15%. The KOPS II pump storage plant went into operation in 2008. 

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East Side Access Project

Project Overview

New York City’s East Side Access Project involves construction of a new subway line needed to relieve heavy traffic congestion between the boroughs of Queens and Manhattan. The line will serve approximately 160,000 commuters daily between Grand Central and Sunnyside rail stations.

Manhattan and Queens will be connected under the East River via the 63rd Street tunnel, a submersed double-deck tube. The submersed tube consists of reinforced concrete sections barged in place on the riverbed. The tube contains operational subway lines on the top deck, while the bottom deck will become operational when the East Side Access Project is completed in 2013.

Geology

The project, awarded to the Dragados/Judlau JV, is located in a range of geology from soft ground to hard rock. Twin 13.7 km (8.5 mi) long Manhattan Approach Tunnels run from the Manhattan side of the submersed tube up to Grand Central station, with geology consisting of schist, gneiss, and granite from 100 to 275 MPa (14,500 to 40,000 psi) UCS.

Equipment Features

The Robbins TBM excavated the Westbound running tunnels, consisting of four short headings that required a design allowing for swift retraction and re-launching.  A second Double Shield TBM, operated by SELI, was used to excavate the Eastbound running tunnels. The Robbins High Performance (HP) Main Beam machine was designed using a segmented, bolt-only cutterhead for easier disassembly. During retraction, the outer components of the cutterhead were removed first. The shielded front section of the TBM, designed as an “umbrella”, was then retracted using hydraulic extensions. The extensions allowed the bottom, side, and roof supports to move radially inwards, reducing the machine diameter from 6.7 m (22.0 ft) when fully extended to just 6.1 m (20.0 ft) with removal of the shield assemblies.

To remove muck, Robbins designed an extensive conveyor system utilizing every commonly recognized type of belt conveyor to transport muck more than 370 m (1,200 ft) away from the jobsite. The system design involved nine separate conveyors handling muck simultaneously from the two tunnels. Two extensible fabric belt conveyors (914 mm/ 36 inches in width) traveled behind the Eastbound and Westbound TBMs, and dumped via a crown-mounted cross conveyor onto a single 1,863 m (6,100 ft) fixed-length conveyor mounted inside the submersed tube.

From the tunnel, muck was transported up the 23 m (75 ft) deep Queens shaft using a fixed-length, steel cable vertical conveyor. Once the muck reached the top of the shaft, it was transferred to the Rail Yard using three overland conveyors and a radial stacker. The second overland conveyor, 37 m (120 ft) in length, crossed Northern Boulevard, a major thoroughfare in Manhattan. This conveyor was designed as a completely enclosed box truss to eliminate debris from reaching the roadway, and sat approximately 6 m (20 ft) above Northern Boulevard and under pre-existing rail lines. Muck was then transferred from the overland conveyors to a radial stacker in the Sunnyside Rail Yard. The radial stacker rotated through 60 degrees to deposit muck in kidney-shaped piles with a capacity of 8,400 cubic meters (11,000 cubic yards).

Tunnel Excavation

The Robbins machine made four drives, totaling 5.2 km (3.3 mi) beneath Manhattan.  The machine first bored 2.3 km (1.5 mi) towards Grand Central Station, and was then retracted 2.0 km (1.2 mi) through the newly bored tunnel, leaving all tracks and tunnel support structures in place. The machine was re-launched at a “Y” shaped intersection to bore three more tunnels at varying elevations.

Boring on the first tunnel commenced on September 30, 2008 with a total of 907 boring hours, and the second, 540 m (1,770 ft) tunnel was finished on February 20, 2009 after 267 boring hours. A third 1.7 km (1.1 mi) long tunnel was completed in February 2010.  By June 2010, the machine had completed its fourth and last 630 m (2,060 ft) long drive after 281 boring hours. The conveyor system operated at over 90% availability during the course of the four headings.

At the time of completion for the Robbins Main Beam machine, the SELI TBM was being readied to bore the third of its four Eastbound running tunnels.

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New Delhi Metro Extension Project

Project Overview

Phase II of the New Delhi Metro Extension Project is an ambitious plan to add 53 km (33 mi) of new rail lines to cut transportation times, in particular for when the city hosted the Commonwealth Games in 2010. Owners Delhi Metro Rail Corporation (DMRC) completed Phase I of the project in November 2006, adding 65 km (40 mi) of track and 59 stations. Phase II, at a cost of USD $1.8 billion, involved multiple soft ground tunnels to be bored by Earth Pressure Balance Machines (EPBMs) between underground stations excavated by cut and cover.

On February 1, 2007, Robbins and Mitsubishi Heavy Industries (MHI) signed a contract with the CEC/Soma JV for two 6.5 m (21.4 ft) diameter EPBMs, back-up systems, and cutting tools. The machines were manufactured by Robbins using components from the U.S., India, and China.

On May 15 2008, the first of the two TBMs was launched from an 18 m (60 ft) deep shaft at the Jor Bagh station site. The machines bored parallel 2.0 km (1.2 mi) tunnels connecting the Udyog Bhawan and Green Park areas in New Delhi, as part of the BC-16 contract. The second machine was launched from the same site during the last week of June 2008.

Geology

The tunnels ranged from 8.6 – 14.0 m (28 – 46 ft) below the water table in sandy silt, silty sand and gravels.

Machine Design

Both EPB cutterheads featured a 55% opening ratio to allow a smooth flow of muck and to avoid clogging the cutterhead. The machines used several types of tungsten carbide bits for boring in soft but abrasive ground and shaft-type screw conveyors to remove water-bearing muck. Continuously erected lining along the length of the tunnel consisted of reinforced concrete segments 275 mm (11 in) thick.

Tunnel Excavation

On September 29, 2008 the first of the two Robbins EPBMs completed its initial bore of 1.0 km (0.6 mi), holing through into the cut and cover Race Course station site. High advance rates of 19 rings installed per day, together with over 90% average availability, contributed to the fast completion.  The machine was then dismantled in a reception pit and transported by road to the other end of the 318 m (1,000 ft) long Race Course site, where it began the second half of its bore to the contract boundary at Udyog Bhawan station. During excavation, the machine achieved a project record of 168 rings, or 202 m (663 ft) in one week—faster than any of the 14 other TBMs working on the project.

By April 2009, all four drives initially planned using Robbins machines were complete. Due to scheduling constraints, Continental Engineering Corporation (CEC) opted to use one of the Robbins machines for a fifth, approximately 567 m (1,860 ft) long drive from AIIMS to Green Park station sites. The fifth and last drive broke through on July 14, 2009. 

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The Abdalajis tunnels

Project Overview

Spain’s high-speed rail network, known as AVE, involves links between the major cities Cordoba, Madrid, Seville, and Malaga. The twin 7.1 km (4.4 mile) long Abdalajis tunnels are part of this rail network and they will contribute to Spain’s overall goal to keep all major cities within four hours travel time from Madrid.

In 2001, the project owner Gestor de Infraestructuras Ferroviarias (GIF) awarded construction contracts separately for each tunnel. The east tunnel was awarded to a Dragados-led consortium called UTE Abdalajis, comprising Dragados, TECSA, SELI, and Jaeger. The west tunnel was awarded to a consortium called UTE Abdalajis Oueste (SACYR S.A., Somague-Engenharia). The two groups shared the main portal site and used nearly identical tunnel boring machines.

Both consortiums chose Double Shield TBMs designed by Robbins for Mitsubishi Heavy Industries. The machines were initially built in Spain by Duro Felguera. They were then assembled onsite with both Robbins and Mitsubishi technicians supervising the assembly.

Geology

The Abdalajis tunnels pass through a variety of rock types, including dolomitic limestone, quartzite, conglomerates, and sandstone. In the deepest part of the tunnels the strata is heavily fractured and karstic conditions in the limestone may harbor considerable amounts of water. The entire span of each tunnel contains more than twenty fractured and faulted areas.

TBMs

The TBMs featured sixty-four 17 inch (432mm) back-loading cutters and could generate a cutterhead thrust of 82,500 kN ( 18,546,734 lb). The Robbins Double Shield design generated a maximum cutterhead torque of 18,700,000 N-m (13,792 lb-ft). Both machines came with probe drills and foam application systems for face conditioning.

Tunnel Excavation

Excavation of the eastern tunnel began in November 2003. The custom design of the TBM allowed it to bore through brittle and heavily fractured rock efficiently. The TBM’s production rates along the first 1,590 m (5,217 ft) were very good with advance rates as high as 34 m (112 ft) per day.

In the middle of the tunnel bore, methane intrusions began to increase. Roughly 800 m (2,625 ft) of fractured clay with methane leaks forced stoppages to ventilate the tunnel. Despite these conditions the TBM kept a constant advance rate and encountered more stable limestone at the end of the tunnel before holing through in January 2006.

The west tunnel machine also began boring in November with similar broken ground and methane gas problems. Similar to the east tunnel TBM, the machine kept constant advance rates despite the unfavorable conditions. The TBM also encountered more stable limestone in the final meters of the tunnel. The west tunnel TBM finished roughly 2.5 months after the hole through in the east tunnel.

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The Pajares Lot 4 tunnel

Project Overview

The Pajares Lot 4 tunnel is part of Spain’s AVE high-speed rail link. The entire 49.5 km (30.8 mi) long tunnel connects Asturias to the Madrid-Valladolid high-speed link. The route was divided into four lots, with two tunnels for traveling both east and west.

Project owner, Administrador de Infraestructuras Ferroviarias (ADIF), awarded the construction contract for Lot 4, a 10.5 km long section of tunnel, to a joint venture of Constructora Hispanica, Azvi, Brues y Fernandez and Copcisa. The joint venture chose a 10 m (32.8 ft) diameter Single Shield TBM to bore the tunnel. The TBM was designed by Robbins and built by Mitsubishi Heavy Industries. The machine was pre-assembled at a shop in Spain and final assembly was completed onsite.

Geology

The machine began boring in August 2006 through sandstone, shale, limestone, molasse, and volcanic rocks with Unconfined Compressive Strengths (UCS) of 40 to 90 Mpa (6-13 ksi). Robbins’ Single Shield design allowed the machine to cope with this fractured and varied rock. The machine could also erect 500 mm (19.7 in) thick pre-cast concrete segments to support the tunnel walls in troublesome geology.

TBM and Tunnel Excavation

The TBM featured 17 inch (432 mm) cutters and was powered by 5,180 kW (6,946 hp) to generate a maximum cutterhead thrust of 16,814 kN (3,780,000 lb). The back-up system for the machine consisted of open gantries.  Tunnel excavation was completed in July 2009.

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