India Welcomes Its Largest-Diameter TBM from China

A 12.19-meter diameter tunnel boring machine (TBM) was packed into 13 containers and shipped to India on March 18 for the country's coastal road tunnel construction.

The TBM was packed at the Changsha First Industrial Park of China Railway Construction Heavy Industry Corporation Limited (CRCHI) and will pass through Shanghai Port and finally arrive at Mumbai, the largest port in India.

With an installed capacity of 7,280 kW, the machine is 80 meters long and weighs 2,300 tons. It will be the largest diameter TBM in India and the largest among all TBMs China has exported to that country.

The project the machine is to participate in is a 1,920-meter tunnel section of a 30.7-kilometer coastal road along Mumbai's west coastal line.

The tunnel construction faces complicated geological conditions that require digging through a compound stratum of basalt, breccias and shale. Such strata are very strong and can resist as much as 200 Mpa of compressive strength.

The great buried depth of the tunnel also adds to construction difficulty.

To solve the problems, the TBM was designed with an eight-spoke and eight panel-typed compound cutter which can dig in complicated strata for a long distance.

A 20-inch large-sized hob is also equipped on the machine to improve its cutter's rock breaking capacity and expand its lifespan.

Not long ago, CRCHI also delivered four TBMs to Bangalore, another city in India, for local metro construction.

CRCHI adjusted design of the machines to improve their performances in breaking through strong rock, boulders and uneven strata.

The export was proof that China-made TBMs are now mass applied in metro projects in South Asian countries.

The largest TBM China has ever exported toIndiapassed inspection and is ready to be separately packed at the Changsha First Industrial Park of China Railway Construction Heavy Industry Corporation Limited. [Photo/sasac.gov.cn]

The TBM is loaded and shipped on March 18. [Photo/sasac.gov.cn]

(Executive editor: Wang Ruoting)