Recently, three Slurry TBMs independently developed by CRCHI have been exported to India after FAT in CRCHI's industrial park of Changsha. The super-large diameter Slurry TBM is the largest one in India, showing company's world-class R&D capabilities in large-diameter TBM. The 12.19m diameter Slurry TBM will serve in the construction of Mumbai Coastal Highway Tunnel. Its total length is 80m; total weight is 2300t; installed power is 7280 KW. The TBM can achieve 350m horizontal turning radius and have 50‰ climbing ability.
It is reported that the 30.7 km coastal road is being constructed along the west coastline of Mumbai by the Arabian Sea, which is the most important highway project in India and will be completed in 2 phases. The tunnel is the first phase of the project, with total length of about 1920m, where the geological conditions are extremely complicated. The composite stratum is composed of basalt, breccia and shale, which has uni-axial compressive strength up to 200 MPa. Moreover, the tunnel has large burial depth, resulting in high requirements for tunnel quality and great difficulties in construction.
In response to the complex geological conditions, CRCHI has tailored 8-spoke 8-panel composite cutterhead, providing powerful guarantee in long distance and complex stratum. To minimize cutterhead blocking and slurry discharging port clogging, large discharging port is designed in the cutterhead center, with several ways of slurry washing ports, improving the fluidity of the slag. To deal with hard basalt, the TBM is equipped with 20’ disc cutters with cutting tool protection block and alloy wear plate, which can effectively improve rock breaking ability and cutterhead service life. In addition, the TBM is equipped with a series of innovative technologies such as dual-chamber indirect slurry control system, dual-circuit Samson automatic pressure maintaining system, high-torque retractable main drive, and high-power slurry circulation system.
The other 2 TBMs that will be used in Bangalore Metro, have completed FAT with few quality problems. It is reported that Bangalore Metro is the most challenging tunnel project in India, which is rather complex in geology: non-uniform strata with large boulders. Soon after, these three CRCHI Slurry TBMs will arrive in India for tunnel construction.