This is the third Tunnel Boring Machine (TBM) in the series of TBMs being used for digging the tunnel being built for the underground metro station. The TBM assembly was lowered 52 feet below ground level into the launching shaft with the help of 4 strand jacks (300 MT capacity each) and megalift with a total capacity of 1200 MT. It takes about 5 to 8 hours for the tunnel boring machine to descend into the launching shaft.
- The 450 metric ton TBM will travel a distance of 966 metres from Gandhi Maidan towards Akashvani underground metro station.
- TBM 3 was lowered into a 32 metre long and 25-metre-wide launching shaft at Gandhi Maidan underground metro station on Wednesday. This TBM will cover a distance of approximately 966 metres from Gandhi Maidan Metro Station to Akashvani Metro Station.
- The weight of the TBM lowered into the underground section of Corridor-II is approximately 450 metric tons. If we compare this TBM with a bus, the weight of a 50-seater bus is approximately 16-17 metric tons, so the weight of this TBM is equal to 28 buses with 50-seater capacity.
It is noteworthy that the work of digging the tunnel with two other tunnel boring machines is already going on in Moin Ul Haq underground metro station. TBM 1 and 2 will travel a distance of approximately 1.49 kilometres from Moin Ul Haq to Patna University where they will be retrieved and re-launched.
What is the launching shaft?
A launching shaft is a structure made of concrete and steel that is built to launch a Tunnel Boring Machine (TBM).
Source: Patna Metro- Press Release | Images Credit: Patna Metro