Peter Kenyon, TunnelTalk
- TBM manufacturers Robbins and Herrenknecht are going head to head on Baku's Metro Line 3 in Azerbaijan.
A Robbins 6.3m EPBM (left) is working alongside a Herenknecht 6.25m EPBM on the twin-bore Baku Metro Line 3
- A Robbins EPB, with a 6.3m (20.7ft) diameter has already been launched by contractor Azerkorpu, which is working for Metrostroy Azerbaijan. A Herrenknecht EPB Shield S-599 with a diameter of 6.25m and a length of 73m is excavating a parallel 3.5km (2.2 mile) tunnel which will run just 15m (50ft) away. Herrenknecht said this week that its machine had already completed 300m of its drive, which started in August, at the same time as the Robbins machine. The drives are part of a much bigger project to extend the aging 23-station 34.6km-long metro system to 76 stations across 119km and five lines by 2040. Herrenknecht is also supplying a wide range of technical equipment and services including conveyor belt systems, mould systems and rolling stock equipment.
- Lok Home, Robbins President, said: "We welcome the opportunity to work alongside our competitors on this and other soft ground tunnelling projects, such as the Emisor Oriente project in Mexico City. Projects such as these give us the opportunity to demonstrate our expertise and capabilities in EPB technology."
Metro Line 3 will start by connecting Cavadxan and Avtovagzal Stations
- So far Robbins has reported the ground to consist of full-face clay similar to London Blue Clay, with no appreciable ground water, pebbles or soil.
- Evan Brinckerhoff, the Robbins Field Services Superintendant, said: "The material is sticky and our initial advance was limited because the pit size was only long enough to muck out with one car. Our machine performance has since improved."
- The Robbins machine features a mixed-ground cutterhead with carbide bits that are interchangeable with disc cutters depending on the geology.
- Four independent foam injection points in the cutterhead evenly consolidate the face in the ground conditions. The design results in decreased cutterhead wear and a smooth flow of muck into the mixing chamber.
- As the TBM advances it is placing 5+1 universal concrete segments. Muck is being stored in separate storage stations for each TBM, and is then trucked away from the site during the day.
The Robbins EPB features a mixed ground cutterhead
- The new Metro Line 3 will connect the existing Line 1, as well as the new bus station. The EPBs are excavating two sections connecting Cavadxan Station and Avtovagzal Station. Once the first leg is completed the machines will continue to excavate between the Memar Ajami-2 Station and an as yet unnamed station near the Azerbaijani Defence Ministry Hospital. The stations are expected to open in 2013.
- Azerbaijan's capital, Baku, has a population of 1.7 million people and is known for its heavily clogged streets. Improved transportation infrastructure is a countrywide initiative in a country which is expected to expand rapidly on account of its substantial oil reserves. The current metro system was opened in 1967, and, like many other ex-Soviet systems, features very deep central stations.
- Robbins EPB to rebuild Azerbaijan waterways - TunnelTalk, May 2009
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