Kolkata: Kolkata Metro Rail Corporation Ltd (KMRCL) plans microsurgery. This is to remove key hurdle of tunnel boring machines (TBMs) that East-West Metro corridor encountered. The Kolkata Metro officials are using international method to remove the hurdle.
The metro officials are facing trouble from the Esplanade to Sealdah stretch. They now plan to employ Australian tunnelling method to remove the hurdle. Five steel H-Piles blocking the route just beyond Esplanade station will be manually removed.
Parashuram Singh, managing director, KMRCL explains that a 40m-long and 3m-wide pilot tunnel will be manually dug linking the two tunnels that the TBMs will excavate. To avoid the earth from caving in, engineers will employ a technique called Fore-poling. As the excavation progresses, sharp metal poles will be employed to form a cover. The H-piles will then be cut by the workers.
Four more such piles will be cut through to clear the hurdle ads Singh.
By middle of August work will begin and continue for three months. Metro officials inform that two TBMs that have by now been lowered underground at the Esplanade station site can commence work by the October end. The officials believe this will aid in meeting the projected June 2021 deadline for the complete 16.6km Kolkata metro project.
Interestingly, the H-Piles date back to the late 70s and early 80s. This was when the when the North-South Esplanade Metro Railway station was being built. It was completed using conventional top-down cut-and-cover technique.
Singh assures that work is going on at good pace. They are able to meet deadlines. A trial run of also carried out on the east-bound line between Salt Lake Sector V and Salt Lake stadium. It was also first full trial run for the east-bound stretch. For west-bound line a full run was conducted previously.
Singh also shares that platform screen doors material has come. Workers have begun installing the doors too.