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Ниагарский тоннель

О проекте

Проект Ниагарского тоннеля – амбициозный проект строительства тоннеля длиной 10, 4 км от Генерирующего Комплекса «Сэр Адам Бек» до реки Ниагара выше по течению от Ниагарского водопада. Со строительством тоннеля генерирующие мощности заказчика – Ontario Power Generation (OPG), – возрастут на 150 МВт и поддержат существующую энергосистему, мощностей которой сейчас едва хватает в пиковые месяцы.

OPG присудила контракт австрийскому подрядчику Strabag AG, Который выбрал для проходки тоннеля ТБМ открытого типа Компании Роббинс. Диаметр машины 14,4 м. С помощью защитового комплекса длиной 105 м и ленточного конвейера за три года было выдано из тоннеля 1,7 миллиона кубических метров породы.

Геология

Трасса тоннеля проходит преимущественно в квинстонских сланцах с включениями участков, представленных известняками, доломитами, песчаниками и алевролитами прочностью на одноосное сжатие до 200 МПа. Известно, что породы, вмещающие тоннель, имеют большое внутреннее напряжение и склонны к пучению. Первичной крепью тоннеля служила стальная сетка, стальные арки, анкера и набрызг-бетон, которые устанавливались по мере продвижения машины. Далее за машиной возводилась монолитная бетонная обделка. Она будет включать гидроизоляционную мембрану, предотвращающую попадание воды из тоннеля в заобделочное пространство и последующее пучение.

ТБМ

ТБМ с главной балкой, или, по-другому, открытая ТБМ, самая большая в мире скальная ТБМ, была смонтирована на стройплощадке без контрольной сборки на заводе. Это заняло меньше 12 месяцев, опережая плотный график поставки. Монтаж такой большой машины без контрольной сборки на заводе и испытаний перед отгрузкой считается беспрецедентным случаем. ТБМ начала бурение в сенгтябре 2006 года.

Эта машина стала также первой, где применялись 20-дюймовые шарошки с задней загрузкой. Такие шарошки имеют увеличенный срок службы, их применение позволяет сократить количество замен шарошек на режущей головке. На режущую головку машины могут устанавливаться как 19-, так и 20-дюймовые шарошки. Машина имеет усилие главной подачи 18462 кН и максимальный момент вращения режущей головки 18670000 Нм.

Проходка тоннеля и мировые рекорды

Пробурив 793 м тоннеля, ТБМ вошла в квинстонские сланцы, где большие блоки породы начали вываливаться из свода тоннеля до установки временной крепи. В некоторых случаях отмечались обрушения кровли тоннеля над режущей головкой на высоту до 3 м.

В конце концов Strabag справился с трудными геологическими условиями, разработав уникальную опережающую крепь из труб длиной 9. Трубы устанавливались в своде тоннеля, образуя своеобразный «зонт». С помощью такой новой технологии удалось уменьшить переборы в кровле тоннеля до примерно 0,9 м. Применяя этот метод, удалось пройти трудный участок длиной примерно 500 м со средней скоростью 3 метра в день.

Согласно новому паспорту временной крепи, устанавливаются анкерная крепь с анкерами длиной от 3 до 4 м, самонарезающиеся анкеры (IBO), стальная затяжка, стальная проволока и набрызг-бетон со стальной фиброй. Обычно бригада проходит половину заходки, затем обирает кровлю и устанавливает анкера. По выполнению полной заходки в 1,8 м, производится окончательная оборка кровли, устанавливается остаток анкерных болтов, стальная сетка, стальная затяжка и наносится набрызг-бетон.

OPG и подрядчик также изменили вертикальный профиль тоннеля, подняв его на 46 м, чтобы уйти из квинстонских сланцев. После 1981 м такой проходки, породный массив стал достаточно устойчивым и от дальнейшего применения опережающей крепи отказались.

Преодолев этот сложный участок, машина достигла мирового рекорда месячной проходки для ТБМ диаметром 11 и более метров. В июле 2009 года ТБМ пробурила 468 метров тоннеля и продвинулась за неделю на 153 метра, преодолев значительные сложности, вызванные неблагоприятной геологией.

Сбойка

День 13 мая 2011 года стал днём окончания проходки. На хорошо организованной церемонии праздновали финальную сбойку открытой ТБМ Роббинс диаметром 14,4 м. 1 марта 2011 машина начала свой путь, зайдя в 300-метровый портальный участок тоннеля, предварительно пройденный в набрызг-бетонной крепи.

Хотя проходческие работы были завершены, оставалось два года работы над проектом. Приблизительно 30% окончательной обделки было выполнено в течение проходки, а две трети работы ещё оставалось сделать. Тоннель с диаметром в свету 12,8 м будет иметь по всей длине обделку из монолитного бетона толщиной 600 мм, покрытого для предотвращения утечек полиолефиновой мембраной. Остаются работы на выходном портале тоннеля, установка затворов и разборка перемычки на реке Ниагара, а также удаление скальной пробки на выходном портале. Тоннель планируется ввести в работу в 2013 году.

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Mexico City Metro Line 12

Project Overview

The Mexico City Metro is one of the world’s largest, with over 200 km (125 mi) of rail and nearly 4 million daily passengers. The 25.4 km (15.8 mi) long route passes through 22 new stations between Tlahuac and Mixcoac neighborhoods. The 7.7 km (4.8 mi) long tunnel represents the capital’s first new route in ten years, and will service thousands of passengers daily.

In 2007, the Mexican Federal District announced plans to build Line 12 of the Mexico City Metro. The ICA consortium signed a contract for a 10.2 m (33.5 ft) diameter Robbins EPBM, its back up system, and cutting tools. The TBM was the largest to ever bore in Mexico and was the first EPB TBM to be assembled at the jobsite using Onsite First Time Assembly (OFTA).

Geology

Geology on the metro line consisted of layers of clay, sand, and boulders up to 800 mm (30 in) in diameter, as the area is part of a drained lake bed. Ground conditions in Mexico City are very unique and thus required extensive vibration monitoring throughout the bore.

TBM

The giant machine utilized a specially designed two-stage, 1,200 mm (4 ft) diameter ribbon type screw conveyor followed by a shaft-type screw conveyor in order to handle the large boulders. For parts of the tunnel where the ground consisted of very soft clays with high water content, muck was removed using a sludge pump rather than conveyors or muck cars.  The machine also featured active articulation, used to prevent segment ring deformation on curves as small as 250 m (820 ft). The spoke-type cutterhead used tungsten carbide knife-edge bits to excavate the soft ground. Additives, as well as two-liquid back-filling, helped control ground subsidence. The two-liquid back-filling system consisted of cement and accelerant, which hardens rapidly and eliminates the need for high-pressure concrete pumps that can disturb the ground. As the machine advanced, it lined the tunnel with 40 cm thick universal concrete segments in a 7+1 arrangement.

The Robbins EPB was launched on February 15, 2010, after just eight weeks of assembly. The launch shaft, approximately 34 m long by 14 m wide by 17 m deep (112 x 46 x 56 ft), was located in one of the most densely urban areas of the city. Due to the small launch pit, the machine bored the first 70 m (230 ft) of tunnel using umbilical cables connected to back-up gantries on the surface. Gantries were then lowered into the shaft successively as the machine bored forward.

Tunnel Excavation

Much of the tunnel was under very low cover of 7.5 m (25 ft), which required careful monitoring of surface subsidence. The project’s location at the city center was in close proximity to a number of structures.  The tunnel route took the machine within 1.5 m (4.9 ft) of a 4 m (13 ft) diameter collector sewer, within 2.0 m (6.6 ft) of building foundations, and just 3.5 m (11.5 ft) below the metro’s active Lines 2 and 3.

Breakthrough

The machine reached the its first station during the last week of April 2010 after boring a total of 495 m (1,624 ft). There were several difficulties with the sludge line, but after engineers redesigned the system it worked exceptionally well. From there, the EPB continued on to six more stations, undergoing routine maintenance at each one. On March 1, 2012, the machine completed its successful tunneling run.

Line 12 of the Mexico City Metro is the longest in the system. The new line carries an average of 367,000 passengers each day, making it the fourth busiest commuter rail route in the capital.

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Locust Street Sanitary Improvements Project No. 6335

Project Overview

In Tigard, Oregon, upwards of 1.8 km (1.1 mi) of gravity sewer were installed by general contractor Northwest Earthmovers Inc. for project owner Clean Water Services. Gonzales Boring & Tunneling was subcontracted to complete three crossings, which formed part of the Locust Street Sanitary Improvements Project No. 6335. The three crossings measured 70 m (230 ft), 183 m (600 ft), and 98 m (320 ft) in length. The 450 mm (18 in) diameter PVC carrier pipe was laid to increase wastewater capacity in the area and stop overflows currently plaguing the system.

Gonzales Boring & Tunneling purchased a Robbins 1.0 m (42 in) SBU-A to complete the three crossings located below houses, neighborhood streets, a small creek, and a service facility.

Geology

Rock conditions on the first crossing consisted of clay and basalt, while the second crossing was composed of basalt at various rock strengths ranging from 48 to 82 MPa (7,000 to 12,000 psi). Sections of the crossings were also interspersed with dirt containing small boulders.

SBU-A Features

Robbins SBU cutterheads can be equipped with a variety of tungsten carbide bits and single or multi-row disc cutters depending on the ground conditions. The SBU cutterhead for the Gonzales Boring crossings was fitted with 165 mm (6.5 in) single disc cutters and larger muck bucket openings to handle the mixed ground conditions.

During the launch of the machine, the SBU-A was welded to the lead steel casing. The cutterhead was propelled forward via torque and thrust from the Auger Boring Machine (ABM). Spoil was removed through openings in the cutterhead called muck buckets and discharged using a full-face auger.

Tunnel Excavation

Workers monitored line and grade, and were able to maintain advance rates of 12 m (40 ft) per 10-hour shift. Using a contractor-designed steering system, the SBU-A holed through within one hundredth of an inch design grade after 183 m (600 ft) of excavation. In addition to having the record for the longest single crossing length, 183 m (600 ft), the machine required no cutter changes after 250 m (830 ft) of boring. A third crossing of 98 m (320 ft) was also excavated in early 2010.  

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Dahuofang Water Tunnel

Project Overview

The Dahuofang Water Tunnel is a large reservoir diversion project that will transport water from high rainfall areas to the dry, heavily industrialized Shenyang region of China. The total length of the tunnel is 85.3 km (53 mi) with over 60 km (37 mi) being driven by tunnel boring machines (TBM) — one of the world’s longest TBM-driven tunnels.

Geology

The project owners awarded construction contracts in three lots, each about 20 km (12 mi) long. Lot 1, awarded to Beijing Vibroflotation Engineering Co Ltd, chose an 8.03 m (26.3 ft) diameter Robbins Main Beam TBM for the project. The machine is responsible for a 20 km (12 mi) bore in migmatite and orthopyre geology.

The Lot 3 contract was awarded to The Bureau of Water Conservancy and Hydroelectric Power Construction, who chose a nearly identical 8.03 m (26.3 ft) diameter Robbins Main Beam TBM for a 16 km (10 mi) long bore. This section of tunnel also passes through migmatite geology, but about two-thirds of the tunnel contains a complex mixture of heavily weathered and fractured rock.

TBMs

Both Robbins Machines include forty-three 19 in (483 mm) cutters and eight 17 in (432 mm) center cutters. The cutters are backloading with frontloading optional. Both machines use variable frequency drive systems and can generate a maximum thrust of 22,934 kN (5,155,767 lb) and the cutterheads of both machines have a torque of up to 6,275,000 N-m (4,628,202 lb-ft).

Robbins also provided the back-up systems for both machines. Each back-up includes a bridge conveyor, transfer conveyor, track-laying area, and rolling gantries among its units. The TBMs use slightly different conveyor systems — the conveyor for TBM 3 is a shorter length with a consequently reduced power-drive system.

The TBM accessory equipment mounts included probe drills and rock bolting systems, which are compact for working in limited space.

Tunnel Excavation

The Robbins TBMs began boring in June and July of 2005. In March of 2006, after only 8 months of boring, TBMs 1 and 3 had advanced 3.8 and 4.0 km (2.4 and 2.5 mi), respectively. The TBMs completed tunneling in 2007.

 

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The Manapouri Hydroelectric Project

Project Overview

The Manapouri Hydropower Station is the largest hydropower station in the country and supplies 5100 GWh of electricity annually. In 1997, the project owners, Electricity Corporation of New Zealand (ECNZ), proposed an expansion of the hydropower station from its then output of 585 MW. The plan included a second 9.6 km (6.0 mi) long tailrace tunnel connecting the underground power station at Lake Manapouri to its discharge point in Doubtful Sound.

In 1997 ECNZ awarded the construction contract, worth US $85 million, to a Joint Venture of Fletcher Construction (New Zealand), Dillingham Construction (U.S.), and Ilbau (Austria). The joint venture awarded the contract to Robbins for one 10.05 m (33.0 ft) diameter Main Beam TBM to excavate the tunnel.

Geology

The tunnel passed through Paleozoic metamorphic and igneous rocks. The metamorphic rocks included gneiss, calcsilicate, quartzite, and intrusions of gabbro and diorite. The tunnel geology also included five sub-vertical fault zones with high potential for water inflows.

TBM

Robbins designed the 10.05 m (33.0 ft) diameter TBM for the mixed face hard rock conditions in the tunnel. The Robbins design was then built by Kvaerner-Markham (U.K.) and shipped to the job site. The cutterhead featured sixty-eight 17 inch (432 mm) cutters with loading from either the front or back. Eleven two-speed electric motors powered the cutterhead with 3,463 kW (4,642 hp), generating a torque of 9,859,400 N-m (7,271,919 lb-ft). The 470 m (1,542 ft) long back-up system, built by Rowa Engineering, included a secondary rock-bolting station and a robotic shotcrete station.

Tunnel Excavation

The Robbins TBM began boring in June 1998 and finished in 33 months. The tunnel progress was divided into four sections, or reaches. During Reach 1, about 1.8 km (1.1 mi) into the bore, the machine experienced few problems. During Reach 2 (spanning 2.4 km (1.5 mi)), the machine encountered heavy water inflows through the fault lines. These inflows reached proportions of 1,300 liters (343 gallons) per second and pressures up to 7.2 MPa (1.0 ksi). These high volumes of inflow necessarily slowed progress throughout Reach 2. Geological conditions improved in Reach 3 (spanning 2 km (1.2 mi)), and by Reach 4 (spanning the final 3.2 km (2.0 mi)) the machine was progressing at a substantial rate.

Despite setbacks due to water, the Robbins TBM suffered no major breakdowns and availability remained high throughout the dig. In addition, total TBM spare parts usage was far below the industry average for this type of job.

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Kárahnjúkar Hydropower Project

Project Overview

The Kárahnjúkar Hydropower Project created the Kárahnjúkar Power Plant to provide 4600 GWh of electricity annually to a nearby aluminum smelting plant. Three dams feed the main Hálslón reservoir and several other dams join the outflow in a combined headrace tunnel to an intake. The intake water travels to the powerhouse through two steel-line vertical shafts and exits from a tailrace tunnel that empties into the Jökulsá i Fljótsdal River.

Project owner Landsvirkjun awarded the construction contract for the hydroelectric project to the Iceland branch of Impregilo S.p.A. The contractor awarded the contract to Robbins for three Robbins Main Beam High Performance TBMs for three lengths of tunnel.

Geology

The machines began boring between April and September 2004 in basalt, moberg, and pillow lava geology up to 300 Mpa (44,000 psi) UCS. A number of fault lines and water inflows were encountered during boring, though the machines made good progress.

TBMs

All three TBMs were the first ever machines designed with back-loading cutterheadsfor 19” cutters. The successful design increased cutter life and reduced the time needed for cutter changes. All of the TBMs were equipped with probe and roof drilling capabilities and were specially designed for the ground conditions. The cutterhead designs featured rock deflectors to protect the cutterhead from fractured and blocky ground, as well as abrasion-resistant wear plates and carbide buttons to bore in abrasive rock.

Tunnel Excavation

Main Headrace Tunnel
By June 2006 the machines had made good progress despite difficult geologic conditions in the tunnels. TBM 1 finished its drive on September 9, 2006 after achieving impressive advance rates with a best month of 864.6 m (2,755 ft) in March 2006. On the same day, TBM 2 tied a world record in its size class after excavating 92 m (302 ft) in 24 hours. The TBM tied the record with another TBM that bored on the Epping to Chatswood Rail Link. TBM 2 finished its initial drive in Fall 2006 and was then disassembled and transported to bore an additional 8.7 km (5.4 mi) long section of the Jökulsá Diversion Tunnel in 2007. The third TBM finished its main tunnel drive on December 5, 2006. All of the TBMs achieved impressive monthly advance rates despite troublesome rock conditions.

Jökulsá Diversion Tunnel
The Jökulsá Diversion Tunnel adds to the water supply capacity of the powerhouse by connecting the Ufsarlón Reservoir to the main headrace tunnel. Work began in April 2007 and finished in April 2008. During the 8.7 km (5.4 mi) drive, TBM 2 continuously turned in record-breaking performances, beating its own record in June 2007 by excavating 106.1 m (348.2 ft) in 24 hours.

In August 2007, the machine achieved the feat again by excavating 115.7 m (380 ft) in 24 hours and 428.8 m (1,400 ft) in one week. The machine excavated at consistently high rates and finished its bore on schedule.

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The Channel Tunnel

Project Overview

The Channel Tunnel, one of the world’s most famous tunnels, is a 50 km (31 mi) tunnel under the English Channel linking Great Britain to France. This link consists of three parallel tunnels running for 39 km (24.2 mi) under the sea. Two Main Rail Tunnels, about 30 m (98 ft) apart, carry trains from the north and from the south. In between the two tunnels is the Channel Service Tunnel, which is connected by cross-passages to the main tunnels. This service tunnel allows maintenance workers to access the rail tunnels at regular intervals.

The contractor for the project, Transmanche-Link (TML) chose five Robbins TBMs to participate in boring the crossings. TBMs were deployed at both the U.K. and France Terminals.

Geology

The majority of the Channel Tunnel passes through chalk marl, much of it faulted. Below the Chalk Marl is a thin 2 m (6.5 ft) band of permeable Glauconitic Marl. This rock is a weak sandstone with a stronger rock strength than the Chalk. The bottom of the tunnels pass through stiff clay with some swelling characteristics. The Chalk is much more faulted and prone to water inflows on the French side of the tunnels.

TBMs

Robbins built five machines for this project, each designed for the geology of a specific length of tunnel.

The high water pressures predicted in the folded and faulted chalk on the French side required the use of three Earth Pressure Balance machines (EPBMs). These machines featured sealed cutter chambers to withstand high water pressures and screw conveyors to carry the cut material from the face.

Robbins built two EPBMs for the French side of each Main Rail Tunnel. These 1,100 tonne (1,200 ton), 8.8 m (29 ft) diameter machines had a cutterhead thrust of 19,613 kN (4,413,000 lb) and generated a maximum torque of 12,748,645 N-m (9,410,000 lb-ft).

The undersea French side of the Channel Service Tunnel also required an EPBM. This machine featured a 5.6 m (18 ft) diameter cutterhead, a cutterhead thrust of 39,227 kN (8,837,000 lb), and a maximum torque of 3,510,781 N-m (2,591,000 lb-ft).

Two Double Shield TBMs were built for the U.K. terminal because fewer water inflows were predicted. Robbins designed these machines to withstand unstable and faulted rock conditions. The 8.36m (27 ft) diameter machines included 13 inch (330 mm) cutters and 65,871 kN (14,821,000 lb) of thrust. The machines generated a maximum 5,727,084 N-m (4,227,660 lb-ft) of torque.

Tunnel Excavation

Machines were deployed on both sides of the tunnels in December 1987. The three French seaward TBMs encountered water inflows almost immediately, forcing the use of the sealed mode of operation much earlier than anticipated. The sealed cutterheads of the machines could withstand 10 bar (145 psi) of water pressure; however, additional measures were required to seal the remainder of the machines against water inflow.

The tail shields of the TBMs were fitted with multiple rows of wire brush seals that pressed against the outside diameter of the concrete segment lining. Grease was injected into wire brushes and the 100 mm (4 in) space between the metallic brushes and the tunnel lining. Grout lines were fitted into the tail shield allowing fine cement grout to be injected into the 152 mm (6 in) annulus between the tunnel lining and the ground. This method sealed the tunnel lining as the TBMs advanced. In spite of the difficult conditions, advance rates improved throughout the boring with the Robbins service tunnel machine averaging 714 m (2,342 ft) per month for the project.

The U.K. machines also experienced some difficult tunneling conditions at the outset. Unforeseen water inflows in a 3.2 km (2.0 mi) stretch caused the machines to slow their progress as each section of tunnel had to be grouted in advance of boring. After passing through this section of tunnel, the machines experienced no further difficulties and began averaging 149 m (490 ft) a week. The Robbins machines on the U.K. side averaged 873 m (2,864 ft) per month and set world records for a best day of 75.5 m (247.7 ft), a best week of 428 m (1,404 ft), and a best month of 1,719 m (5,640 ft) — all of which have yet to be beaten.

Muck transport on both sides of the tunnel was complicated but worked well. In the U.K. a rail system of 500 muck cars transported muck back to the access adit at Lower Shakespeare Cliff and fed it onto a high-speed conveyor. The conveyor then dumped the muck into lagoons behind sea walls in the English Channel. In all, about 4 million m3 (5.23 million cubic yards) of chalk were dumped at the site. The area, called Samphire Hoe, is now a popular park.

On the French side muck was crushed and mixed with water in a chamber at the bottom of the Sangette access shaft. It was then pumped up the shaft and behind a 30.5m (100 ft) dammed reservoir.

In December 1990, the French and British TBMs met in the middle and completed the Channel Service Tunnel bore. In all of the tunnels the French TBM was dismantled while the U.K. TBM was turned aside and buried.

The Main Rail Tunnels met on May 22, 1991 and June 28, 1991. Both accomplishments were celebrated with breakthrough ceremonies to commemorate the building of one of the world’s longest and most ambitious undersea tunnels.

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Boston Harbor Project

Project Overview

The Boston Harbor Project includes one of the largest wastewater treatment plants in the United States. The project required two undersea tunnels to carry wastewater to and from the new treatment plant. One tunnel conveys treated waste water through a 15.2 km (9.4 mi) long effluent outfall tunnel beneath Boston Harbor. The outfall tunnel transports the water from the Deer Island Treatment Plant into Massachusetts Bay. Since the completion of the project in 1998, effluent discharges into Boston Harbor have ceased and concentrations of toxic bacteria, waste solids, and nitrogen have decreased dramatically.

In 1990, The Massachusetts Water Resource Authority awarded the construction contract to Kiewit-Atkinson-Kenny Joint Venture. The contractors selected an 8.1 m (26.5 ft) diameter Robbins Double Shield TBM to bore and install the lining in the effluent outfall tunnel.

Geology

The prominent rock type along the tunnel is Cambridge argillite in beds 1 mm to 8 cm (.04 to 3.15 in) thick with occasional 1.5 m (4.9 ft) formations. Volcanic flows and occasional tuff deposits are also embedded in the argillite. Other geologic features include igneous dikes and sills of diabase with some basalt, andesite, and felsite.

TBM and Back-up

Robbins built the Double Shield TBM to handle the variable geology of the undersea tunnel. While in “double shield mode” the machine simultaneously installed pre-cast concrete lining segments while excavating. This feature gave the machine a faster overall advance rate than with the sequential operation of “single shield mode”.

The machine’s cutterhead drive consisted of eight electric motors generating 2520 kW (3360 hp) and supplying 3665 kN-m (2,700,000 lb-ft) of torque to the cutterhead. The cutterhead thrust was 111,350 kN (2,500,000 lb) and the machine’s 50 – 17 in (432 mm) diameter cutters could be changed from behind or in front of the cutterhead.

The source of cutterhead thrust could also be changed depending on boring conditions. In good conditions (self-supporting ground, usually hard rock), the machine would bore in “double shield mode,” where thrust reacted through a conventional gripper system into the tunnel walls. In soil or fractured zones where the tunnel walls were too weak, the machine would operate in “single shield mode”, where the thrust reacted directly to the tunnel lining segments via a set of auxiliary cylinders in the tail shield.

The TBM towed a back-up train with eight 10.7 m (35 ft) long double-deck gantries, via hydraulic cylinders. The upper decks of the gantries housed the two main 2000 kVA transformers, electrical control cabinets, dust scrubber system and auxiliary equipment. Flexible 1.5 m (4.9 ft) diameter ducting extended from a storage cassette mounted on the last back-up gantry to provide ventilation. A double-track rail system installed on the first six gantries provided storage for rail cars carrying pre-cast segments and pea gravel for temporary segment support, rails and ties.

Tunnel Excavation

The TBM began excavating from the access shaft in July 1992. Early in the drive, the TBM battled more blocky rock than predicted in the geological reports. Hard rock and water inflows continued to slow progress throughout the drive.

In 1993 and again in 1995 and 1996, hard rock and heavy water inflows required face grouting and slowed TBM progress. Most of the water inflows reached rates of 19,000 to 26,600 liters (5,019 to 7,027 gallons) per minute. Probe drilling and grouting in these sections resulted in slower TBM advance rates.

From March 1996 onward, TBM excavation continued concurrently with hand excavation of the crossover adits. The machine broke through on September 19, 1996 after excavating over 15 km (9.3 mi). The TBM achieved a best day of 44.2 m (145 ft) and a best week of 195.1 m (640 ft).

This TBM’s achievements are remarkable considering the extremely high volume of water inflow and large variations in geology throughout the drive.

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The Epping to Chatswood Rail Link

Обзор проекта

Городская железнодорожная сеть Сиднея была расширена строительством линии Эпинг – Чествуд. Проект состоял из двух параллельных тоннелей длиной по 12,5 км каждый. Правительство штата Новый Южный Уэльс присудило контракт на строительство совместному предприятию Theiss Hochtief (THJV), учрежденному австралийской и немецкой строительными компаниями.

В 2002 году подрядчик заказал Компании Роббинс две ТБМ открытого типа диаметром 7,2 м. Машины пробурили два тоннеля, начав работу от автобусной станции «Дели», расположенной приблизительно в центре трассы тоннелей. При этом были достигнуты впечатляющие скорости проходки.

Геология

Оба тоннеля проходят сквозь свиту песчаников Hawkesbury и отложения сланцев Ashfield. На трассе находится один разлом, расположенный в районе станции Macquarie Park примерно в 2 км от начала проходки первого перегона

ТБМы и конвейеры

Каждая из двух ТБМ открытого типа располагает мощностью на режущей головке в 2300 кВт и максимальным усилием подачи в 1400 метрических тонн. Компания Роббинс внесла в проект обеих машин ряд новаторских идей. Так, уникальный перекатной защитовой комплекс позволил производить укладку монолитного бетона в обратный свод тоннеля непосредственно во время бурения. Такой метод создания бетонного дорожного полотна, не останавливая проходку, позволил применить самоходное оборудование на шинном ходу и организовать быструю укладку рельсового пути.
Специально для этого проекта Роббинс создал также оригинальную конвейерную систему, состоящую из пяти работающих совместно конвейеров: двух горизонтальных, двух вертикальных и одного отвалообразователя. Смонтированный в своде тоннеля, горизонтальный конвейер работал на длине 6 км трасы тоннеля, более чем на 80% состоящей из кривых.

Проходка тоннеля

Машины начали бурение тоннелей в августе и сентябре 2003 года соответственно. Обе машины закончили проходку в Эпинге в июле 2004 года. Вторые перегоны начали бурить в ноябре 2004 года и машины пришли в Четсвуд в июне и июле 2005 года соответственно. За это время одна из машин поставила мировой рекорд скорости проходки в своём классе, пробурив за сутки 92 м тоннеля. Лучшим результатом проходки за неделю стали 368 м. Средняя недельная скорость проходки для всего проекта составила 200 м. С машинами было мало проблем и они были готовы к работе 80% общего времени строительства.

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New Wuchieh Diversion Tunnel

Project Overview

The New Wuchieh Diversion Tunnel is part of a water transfer system that feeds into the Sun-Moon Lake Hydraulic Power Plant, one of the largest single power sources in Taiwan. Project owners Taipower commissioned the new 6.3 km (3.9 mi) long tunnel after the original Wuchieh Diversion Tunnel was found cracked and degraded after 70 years of service.

The tunnel stretches from its source at Sun-Moon Lake to the intake structure at the hydraulic power station. The new tunnel, along with another water transfer tunnel feeding into Sun-Moon Lake, will increase the output of the power plant to 7,600,000 KWh annually.

Taipower awarded the construction contract for the new diversion tunnel to Kumagai Gumi Co. Ltd. The contractor chose a 6.2 m (20.3 ft) diameter Robbins Main Beam TBM for the project.

Geology

The tunnel passes through quartzite, sandstone, and slate. There are also some areas containing broken rock.

TBM

Robbins rebuilt a used 6.2 m (20.3 ft) diameter Main Beam TBM for the New Wuchieh Tunnel. The refurbished TBM featured 17 inch (432mm) wedge-lock cutters and 1,890 kW (2,534 hp) of cutterhead power. The 380 tonne (420 ton) machine also generated a maximum torque of 1,774,415 N-m (1,307,550 lb-ft) at the cutterhead.

Tunnel Excavation

The TBM began boring in July 2000 and finished in 24 months on June 7, 2002. The TBM’s average monthly advance was over 400 m (1,312 ft) and it acheived a best month of 650 m (2,133 ft). After half of the tunnel had been excavated some broken ground was encountered and tunnel linings such as ring beams, mesh, and shotcrete were applied. Some portions of the tunnel were also lined with cast iron segments for additional support.

In September 2001, Typhoon Toraji hit the area and flooded the site with mud, water, and rocks. Some of the shipping containers containing spare parts, cutters, and workshops were completely submerged. Fortunately, the flood level stayed below the working tunnel level and operations were merely delayed. The remainder of the excavation went smoothly and the finished tunnel was celebrated as the first tunnel ever completed solely by TBM in Taiwan.

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