Robbins EPB Attains
City-Wide Record in Chengdu
TBM Bests 11 Other Machines with March Advance Rate
 In March 2010, contractors celebrated a city-wide excavation record on the Chengdu Metro, of 457.5 m (1,500 ft) in one month. The 6.26 m (20.5 ft) diameter Robbins EPB has excavated at rates of up to 24 m (79 ft) per day — faster than any of the 11 other TBMs working on the project. The machine began excavation of Line 2, Lot 18 of the Chengdu Metro in January 2010, as part of a project for the China Railway Construction Corp Ltd. (CRCC).
By May, the machine had excavated approximately 1,000 m (3,280 ft) of the 2.7 km (1.6 mi) long tunnel, to be bored in two sections. Cutter wear was minimal, with no cutters changed since the start of boring. “These achievements are due to the strong support of field service during assembly, commissioning, maintenance, and excavation,” wrote Mr. Li Quanshe of CRCC in a letter to Robbins.
The Robbins machine was designed to excavate a matrix of alluvial geology found nowhere else in China, consisting of highly permeable pebbles, sand, and clay. A mixed ground cutterhead, mounted with 17-in. diameter disc cutters and carbide bits, was manufactured specifically to effectively excavate the geology. A foam injection system stabilizes running ground, with each cubic meter of foam mixture able to stabilize about 40 rings of ground. Subsidence is being intensively monitored and crews are trained to utilize probe drilling and ground consolidation if settlement is detected.
China’s Chengdu Metro will open in three stages, with Line 1 operational by 2010. The 26.7 km (16.6 mi) long Line 1 will provide service between Honghuayan and Shiji Square stations at speeds of 80 km/h (50 mph). The 50.6 km (31.4 mi) long Line 2, for Chengdu Metro LLC, (with 17.6 km/10.9 mi of underground tunnels) will include 26 stations between Longquandong and Shiniu areas. Seven lines totaling 274 km (170 mi) are planned to be operational by 2035, and will service 13.1 million daily passengers.
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Record-Breaking Herrenknecht TBM
to Extend Highway Network in Italy
Currently, a busy section of the A1 highway in Italy between Bologna and Florence is being extended as part of the Variante di Valico extension project. In the future, this section will accommodate at least three traffic lanes on both sides.
The 6-7 lot of a new alternate route includes the construction of the Sparvo Tunnel, the profile of which will set a new record in mechanized tunneling as far as the drilling diameter is concerned. The tunnel will consist of two parallel-running tubes with a length of 2.5 km each, which will both accommodate a three-lane road. Due to the size and the geological conditions, the construction of the tunnel is considered to be the most challenging part of the overall project. The Italian contractor decided to use mechanized tunneling technology to improve work safety and to accelerate the work. Therefore, the Chieti-based company — Toto Costruzioni Generali S.p.A. — ordered a tunnel boring machine (TBM) from Herrenknecht of Germany. Toto will carry out the tunneling works in loose soils with local presence of gas using EPB technology on a total length of 5 km. The Sparvo Tunnel is part of the project awarded by Autostrade per l’Italia S.p.A. to a joint venture comprising Vianini Lavori S.p.A., Toto Costruzioni Generali S.p.A. and Profacta S.p.A.
In order to produce the two 2.5-km long tubes of the Sparvo Tunnel, Herrenknecht is developing and building an EPB Shield (Earth Pressure Balance Shield) with an exterior diameter of 15.55 m, a weight of 4,300 tonnes, a cutterhead power of 12,000 kW and an overall length of 120 m. After completion at the Schwanau plant, the world’s largest tunnel boring machine will then start its work in Italy.
Preparations for the assembly of the record-breaking TBM have already started in Schwanau. A tight time schedule has been set for the construction of the Sparvo Tunnel. In line with the current planning, the machine is expected to start tunneling near Florence toward the north as early as in the first half of 2011. The 6-7 lot is the last section of the Variante di Valico project which will considerably reduce the travelling time between Bologna and Florence for up to 90,000 vehicles per day after the alternate route is opened according to schedule at the end of 2013.
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NFM Breakthrough in Barcelona Metro
The NFM Technologies tunneling machine charged with excavating Line 9 of the Barcelona Metro has made its breakthrough of the section excavated using the hard rock cutterhead fitted at the beginning of 2010. The client UTE LINIA 9 (a group of Spanish and Catalan companies — FCC/FERROVIAL/OHL/COPSICA/COPISA) is very satisfied with how the work has progressed and with the resistance of the cutting tools throughout this particularly tricky section. The 11.95 m diameter dual-mode machine has excavated 960 m in three months through fractured ground featuring large blocks of granite and schist. The machine has reached Guinardo station, where a second change of cutterhead is currently under way.
The tunneling machine will continue to excavate through 4,400 m to Mandri station using the initial EPB cutterhead. It will bore through approximately 4,000 m of clay soil before once more coming across rocky soil made up of granite and schist for the last 500 m. NFM Technologies has supplied a solution for optimizing the initial cutterhead in order to cope with ground variations (soft ground/hard ground) and to cut through rock without being replaced again.
The Spanish client has highlighted the efficient support supplied by NFM Technologies during all of its technical operations. To date, the tunneling machine has bored through more than 7 km on Line 9 of the Barcelona Metro.
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Balfour Beatty Turns to Atlas Copco
for Devils Punchbowl Tunnels
13,000 Holes Drilled for U.K. Highway Project
At 1.8 km long running beneath the Devils Punchbowl, the twin road tunnels of the Highways Agency A3 Hindhead Tunnel project will be the longest non-estuarial tunnels in the UK. Balfour Beatty, main contractor for the project, reached the stage where they were faced with the task of core drilling approximately 13,000 holes in the walls and floors of the tunnels.
The holes in the tunnels' shotcrete walls needed to be 40 mm diameter, 150 mm deep and drilled every 750 mm at an upward angle using rigs mounted on the concrete shutter units. The holes in the tunnel floor needed to be 137 mm diameter and 220 mm deep drilled vertically every 2 m using a portable drill rig. Both sets of holes are needed to ensure total stability of the automatic concrete shutter units when forming the concrete tunnel lining sections in-situ.
Chosen for core-drilling the walls were eight Atlas Copco LCD 1500 hydraulic core drills, two per shutter, each powered by an Atlas Copco 3 phase electric, 20 liter/minute hydraulic power pack.
Dave Carver, tunnel agent for the project, is very pleased with the performance: “The drilling rate, reliability and robustness of the Atlas Copco LCD 1500 core drills are far better than the electric core drills being used initially and has saved us a lot of time. When you have thousands of holes to drill, time saved on every hole and lack of breakdowns soon adds up.”
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New Morgan Sindall Becomes
One of UK's Largest Forces in
Construction and Infrastructure
A new force in construction launched June 7 as Morgan Sindall became one of the largest construction and infrastructure firms in the United Kingdom.
The new business, Morgan Sindall, has been created following a merger of Morgan Sindall Group plc’s construction and infrastructure divisions which operated under the Morgan Ashurst, Morgan Est, and Morgan Professional Services brand names. Morgan Sindall Professional Services will trade as a separate company and will continue to work with internal and external customers.
Graham Shennan, formerly managing director of Morgan Ashurst, heads up Morgan Sindall as new managing director.
The new company employs approximately 4,800 people and provides integrated services on a number of large, complex projects for customers including BAA, Airbus, Defence Estates, Highways Agency, London Underground, National Grid, E.ON and Network Rail.
Major schemes Morgan Sindall is currently involved with include the £400 million Lee Tunnel project, a joint venture scheme for Thames Water, appointment to the Highways Agency’s managed motorways framework (with JV partner BAM Nuttall) worth up to £2 billion, and a circa £500 million, 10-year framework contract to deliver a programme of capital asset replacement and reinforcement for E.ON’s Central Networks eastern region.
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Robbins EPB Attains City-Wide Record in Chengdu
