In the process of procuring four TBMs
The construction work on the first phase of underground network for the Corridor II will soon be on fast track as one of the important machineries used for constructing the underground rail network, the tunnel boring machine (TBM), has reached the city. The tunnelling work on the underground section of the Corridor II is likely to be completed within 24 to 30 months once the work begins on the proposed network.
The Delhi Metro Rail Corporation (DMRC), the nodal agency for the Patna metro project, is in the process of procuring four TBMs from a China-based company-CRCHI, of which two have already arrived. The DMRC officials said TBMs can usually bore nearly 8-10 metre per day depending on the geological conditions and if the conditions are tough, it could slow down the progress. “The machine is specialized in such a way that the concrete tube and the debris clearance take place simultaneously. The entire tunnel work is mechanical without any human intervention. The machines will be operated by a team of around 35 people,” an official said.
The 7.9km-long underground tunnel for metro rail has been proposed from Rajendra Nagar to Frazer Road, consisting of seven underground stations-Rajendra Nagar, Moin-ul-Haque Stadium, Patna University, PMCH, Gandhi Maidan, Akashvani and Patna Junction (interchangeable station).
According to officials, it will take around a month to assemble the TBM, following which the machine will be put into action for making underground line by using earth pressure balancing (EPB) technology, with concrete lining made up of precast tunnel rings. TBMs are an integral part of any metro rail project as it bores the earth, builds tunnels and helps in creating the underground network for the
system. The machines are nearly 90-metre long and its diameter is 15-metre.
The sources at metro rail project said the two TBMs, which arrived from China through shipping, have been put up for assembling at Moin-ul-Haque Stadium, where construction work on underground station has been going on. “The machines will be lowered into two dug up areas, made at a distance of 10-metre. The construction of twin tunnels from Moin-Ul-Haque Stadium will start in March 2023. The
Corridor II underground twin tunnel network includes two metro rail tunnel’s lines, one north-bound and another south-bound,” the sources said.
The Corridor II (Patna Junction-Patliputra Bus Terminal) will be 14.5km-long, including 6.6km long priority corridor- Malahi Pakri, Khemnichak, Bhoothnath, Zero Mile and New ISBT, which is the part of elevated section. It will be ready by 2025. The work on 7.9km underground network will be completed by 2026.
The estimated cost of Patna metro project is Rs 13925.50 crore (excluding land acquisition cost, which is entirely to be borne by the state government). Twenty percent of the project cost will be borne by the state government while 20% by the Centre and the remaining 60 per cent will be borrowed as loan from JICA.