Tender launched for Chennai twin tunnels
22 January 2021Chennai Metro has issued a tender (Phase 2/CP06/UG06) for the construction of twin TBM-bored tunnels and five underground stations in the Indian city.
The alignment length of 10.8km will comprise single-track tunnels of 5.8m minimum internal diameter and will extend from Kolathur retrieval shaft to Nathamuni launching shaft. Also included is the construction of five underground stations at Kolathur Junction, Srinivasa Nagar Station, Villivakkam Suburban Station, Villivakkam Bus Terminus Station and Nathamuni Station, along with associated structures and other civils works. The tender also includes cross passages to be excavated by NATM.
Chennai’s geology comprises a cocktail of various formations, principally recent alluvium;
consolidated tertiary sediments and conglomerates; and crystalline rocks, including granites, gneisses, basic and ultra-basic intrusives. The crystalline rocks are weathered and jointed-fractured.
Chennai Metro has specified that the contractor shall deploy four OEM-certified, newly refurbished tunnel boring machines (out of which a minimum of two must be sourced from Japan).
The closing date for bids is 7 May 2021.
