Terratec has announced the delivery of a 3.2m diameter Open TBM for the Municipal Corporation of Greater Mumbai’s (MCGM) Amar Mahal I Tunnel Project in Maharashtra, following the successful Factory Acceptance Test (FAT). The machine is now ready to be shipped to the site where contractor Soma Enterprise Limited will complete a water transfer tunnel in Mumbai, India. The first machine delivered last year is already working on the Amar Mahal II Tunnel Project and it is progressing smoothly.
This machine is designed to work efficiently in the geology expected along the project alignment. The project requires the TBM to have a modular design that allows it to be launched and potentially received via shafts (or alternately disassembled inside the tunnel). The robust CutterHead is equipped with 18 heavy-duty back-loading disc cutters. The VFD controlled electric motors enabling the cutter head to rotate at over 10rpm with optimum torque.
To allow safe tunnelling through all the sections of the alignment, the machine has been designed with very efficient ground supporting equipment which includes a fixed probe drilling unit, two rock bolting drills, shotcrete pump and a steel arch erector.
The AMT-I tunnel is one of a number of projects presently being carried out by the Municipal Corporation of Greater Mumbai (MCGM) to augment and improve its water distribution system in order to meet increased demand and ensure reliable supply.
MCGM has taken up several projects for augmentation of water sources, improvement of the distribution system and management of demand and supply. MCGM has encountered problems with leakages, contamination, encroachments, inaccessibility and several trunk distribution mains in the city are being replaced by constructing tunnels as long-term solutions.
The project will consist of two TBM drives totalling 9,683m in length between three shafts. The first drive runs from Hedgewar Udyan to Pratiksha Nagar and the second drive runs from Pratiksha Nagar to Parel at an average depth of 80 to 90m for water transfer.
One of the special features of the TBM is that it has been designed to be disassembled with all components being removed through the completed tunnel. The largest part is the cutterhead and this is designed with a flange that allows the cutterhead to be removed in two pieces.