Mumbai Trans Harbour Link project: German tech to expedite construction work in sea

The Mumbai Metropolitan Region Development Authority (MMRDA)-appointed contractor is using German rigs to apply the reverse circulation drilling (RCD) method in the sea to expedite work on the Mumbai Trans Harbour Link (MTHL) expeditiously.

The RCD is an environmentfriendly technique, as compared to the other conventional methods as it does not use bentonite, which can damage the water body. The MMRDA Commissioner R A Rajeev, who visited the site on October 28, launched the first of these rigs and instructed the contractor to deploy more of these to ensure the project is completed within the September 2022 deadline.

A senior MMRDA official said, "The MTHL bridge is 22km long, of which 16.5km will be over the sea. Therefore, an environment-friendly method is adopted to protect the seabed." Interestingly, this makes the bridge being built over the Thane creek, the country’s longest sea bridge. At present, the Bandra-Worli sea link is the longest one.

The official further explained, "The RCD method is faster and is proven to be successful, as compared to conventional methods for carrying out piling work in hard rock -the machine drills through the rock and the cut material gets mixed with water, which is brought to the surface by using pressurised air. Also, high drilling penetration rates can be achieved using this method, without unduly disturbing marine life."

The project is being carried out in three 'civil packages'. Package 1, involves the construction of the 10.380km long bridge section and so far, 12.28 per cent progress has been achieved.

Similarly Package 2, involves the construction of the 7.807km long bridge section and is showing 5.37 per cent progress, while Package 3 involves the construction of a 3.613km long viaduct and has progressed by 5.4 per cent so far, according to the MMRDA data.

As the project will pass through the Bhabha Atomic Reserach Centre(BARC) and the Sewri mudflats, "View barriers will be installed for the safety of sensitive installations at BARC. Also to protect migratory birds like flamingos, which usually flock near the mudflats, noise barriers will be installed up to a stretch of six kilometres of the total 22km bridge length, so traffic disturbance can be minimised," the official said.

As on November 2018, nine per cent of the project, which began eight months ago, is complete. The bridge will begin from Sewri, South Mumbai, go across the Thane creek and end at Chirle village, near

Nhava Sheva in Navi Mumbai. It is expected to save fuel and travel time, once it is complete. The estimated cost of the project is Rs 22,000 crore and the bulk of the funding is being provided by the Japan International Cooperation Agency (JICA), Rs 17,843.

As on November 2018, nine per cent of the project, which began eight months ago, is complete. The bridge will begin from Sewri, South Mumbai, go across the Thane creek and end at Chirle village, near Nhava Sheva in Navi Mumbai