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| HIGHLIGHTS - November 2009 |
Tunnel Boring Machine in operation
Construction work on the Gastau tunnel begins rock excavation
Schahin Engenharia pioneered the Tunnel Boring Machine (TBM) excavation method in Brazil in a rock tunnel. This is part of the second phase of the building of the Gastau tunnel, which is a segment of a Petrobras gas pipeline that is to link the natural gas treatment unit in the town of Caraguatatuba, on the São Paulo State coast, to the inner-state town of Taubaté.
Of the 160-kilometer gas pipeline, Schahin is responsible for building the 5 kilometer-tunnel, 4.7 kilometers of which involve rock excavation. During the first stage, which comprised the first 300 meters, the company relied on the conventional New Austrian Tunneling Method (NATM), involving hydraulic excavators, loaders, dump trucks, explosives and the application of shotcrete. At this stage, the lining of the tunnel was carried out by installing metal crankshafts and sprayed concrete.
When it came to excavating the rock, however, Schahin innovated by obtaining a tunneling machine that is currently in operation, to achieve productivity gains and to improve safety during the construction work without jeopardizing costs.
The German equipment consists of an integrated system that excavates rock and does all the retaining, including the placement of rings, treatment and monitoring, thus ensuring safe construction that complies with all requirements of projects with these characteristics.
Furthermore, the German tunneling machine relies on the latest boring technology and is equipped with a modern geotechnical survey device that minimizes the risk of accidents and downtime.
Anita
Also referred to as “tatuzão” [the big armadillo], the tunneling machine is about 130 meters long, with a 6.20 meter diameter; it weighs some 750 tons and its average daily excavation capacity is about 20 meters. The equipment is operated by employees of Ghella, an Italian company with substantial experience in this kind of construction work.
Prior to putting the tunneling machine to work, an event held in September celebrated the completion of the machine’s assembly. This was attended by Schahin’s executive board and by Petrobras and Ghella representatives. The event included naming the machine, which was given the moniker Anita, in honor of Anita Garibaldi, a symbol of dedication and courage in Brazil and in Italy.
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