It is acknowledged that the Bangalore metro project with frequent stratum variations is one of the most challenging metro construction projects which uses the TBM method. The total length of the section is 855 meters, among which, 250 meters surrounding rock strength is up to 200 MPa of full section hard rock, 350 meters compound stratum with a large number of boulders, hard bottom and soft top, and 255 meters consisted of sand or backfill stratum.
Apart from this, the TBM passed through the shallow buried depth section of the old town of Bangalore city with dense residential areas. The minimum buried depth is 7.6 meters, and the geological conditions are very complicated. In order to overcome the variable geology and shallow buried depth, CRCHI carried out a number of specific designs for this hard rock/slurry TBM to ensure smooth tunnelling under complicated geological conditions. The TBM is equipped with heavy composite cutterhead, active hinge + stabilizer, advanced geological detection and grouting system, excavation management system, and other features.
CRCHI supplied 4 sets of TBM for this project, and the Urja TBM will be transported to the launching shaft at the north end of Cantonment Station, where it will continue to construct a tunnel between the Cantonment and Pottery Town stations in the city.