Overcoming key hurdles.
Shaping the country’s longest underground metro in India’s financial capital is not without its challenges, several of which we have helped MMRC to overcome.
Mumbai is the second most congested city of the world after Moscow, and land acquisition has proven to be a never-ending challenge for the state government. Coupled with socio-political hurdles, this meant prolonged court proceedings before landing a partial consensus that had already delayed several deliverables before the project.
We supported the client in scouting for alternative options to land acquisition hurdles so as to avoid further deferring MMRC’s priority plans for phase 1 (from SEEPZ to BKC stations - 9 out of the line’s 27 stations) revenue operation launch by September 2022.
Mumbai’s subsurface is a varied mix of ground types, ranging from basalt to soft volcanic tuffs, shale and breccia. These combined to make the tunneling conditions particularly difficult.
Furthermore, the Aqua Line route passes through South Bombay, featuring many buildings dating back to India’s colonial past as par of the British Empire, and listed as monuments of national importance. This technically barred the client from deploying tunnel boring machines and traditional cut and cover stations at specific underground locations.
The solution found by Egis together with our consortium colleagues was the NATM (New Austrian Tunnelling Method), considered less intrusive than traditional tunnel boring techniques, so as to avoid infringement at specific heritage locations. Additionally, given the geological challenges, the teams on TBM/NATM remained extra vigilant while assessing the ground conditions before making their first breakthrough.