Thane-Borivli twin tunnel project will displace 1.4 lakh trucks’ worth of soil

The twin tunnels, spanning 10.25 km each, will pass beneath the Sanjay Gandhi National Park

Work on the Thane-Borivli underground twin tunnel, passing beneath the Sanjay Gandhi National Park, is set to commence in the coming months. The project is expected to excavate around 3.5 million cubic metres of soil, which equates to the capacity of approximately 1,40,000 large trucks. Three potential dumping sites have been proposed for the soil disposal.

An MMRDA official involved in the project said, "The Thane-Borivli Underground Tunnel Project (Package-2) is anticipated to excavate about 3.5 million cubic metres of soil. Megh Engineering and Infrastructure Ltd, the contractor, has identified three alternative dumping sites near Mankoli, Kalher, and Ranjnoli for this material.

Initially, 30,000 cubic metres of soil will be used for developing the casting yard at Kasarvadavli. All necessary permissions will be obtained from regulatory authorities before soil disposal, as per the rules."

To transport the total excavated soil, trucks with a capacity of 25 cubic metres each would be required, resulting in 1,40,000 trips for the full 3.5 million cubic metres. Transporting just the 30,000 cubic metres would take 1,200 trucks.

The tunnel project is divided into three packages. Package 1 will feature a 5.75-km tunnel on the Borivli side, Package 2 will see a 6.05-km tunnel on the Thane side and Package 3 will cover the procurement and installation of electrical, mechanical and fire systems, along with ventilation.

The total length of the tunnel is 11.8 km, with an outer diameter of 13.05 metres (two lanes per tunnel plus one emergency lane), and cross passages every 300 metres. The project will also incorporate a drainage system, smoke detectors, and jet fans to maintain clean air inside the tunnel.

This tunnel will reduce travel distance by 12 km and save motorists about one hour, offering significant reductions in time and fuel costs. The project, with an estimated cost of over '14,400 crore, is expected to ease congestion on Ghodbunder Road by providing a quicker alternative route between Thane and Borivli.

The twin tunnels, spanning 10.25 km each, will pass beneath the Sanjay Gandhi National Park, connecting Tikuji-Ni-Wadi in Thane to the Western Express Highway in Borivli. The Mumbai Metropolitan Region Development Authority (MMRDA) will use a Tunnel Boring Machine (TBM) to minimise disruption to the park's biodiversity. The entire project is expected to take five and a half years to complete from the day the tender is awarded.

The tunnel will allow vehicles to travel at a top speed of 80 km/h, reducing travel time by 40 to 45 minutes and saving an estimated 10.5 lakh metric tonnes of fuel. It will also contribute to a 36 per cent reduction in carbon dioxide emissions. Measures such as cross tunnels, smoke detection systems, and jet fans will ensure clean and fresh air within the tunnel.

1,40,000
No. of trips large trucks will make to carry the mud