On March 27, 2024, the cutter head of the Φ15.4m slurry TBM “CREC 1398” was successfully delivered into the shaft and assembled with the main machine at the No. 3 launch shaft site of Chongtai (Chongming District – Taicang City) Yangtze River Tunnel.

Designed and manufactured by China Railway Engineering Equipment Group Co., Ltd. (CREG), the super-large diameter slurry TBM is 128m long and weighs about 4000t. It is composed of a cutter head, a main machine, a connection bridge and four back-up gantries, which is the world’s largest diameter slurry TBM for the high-speed railway cross-river tunnel. The tunnel has the total length of 14.25km. The slurry TBM will excavate 11.325km by blind heading under the Yangtze River with a maximum water and earth pressure of 10.2 bar and a maximum depth of 89m.

To deal with the super-large diameter, super-long distance, super-high water pressure, super-deep overburden and other challenges, CREG has customized this slurry TBM. The wear-resistant performance of the key parts including the cutter head, main bearing, main slurry discharge pipe has been guaranteed by increasing the thickness of wear-resistant plates and the quantity of wear monitoring devices. The TBM structure is optimized to ensure that the strength of main drive inner and outer seals can satisfy the pressure-bearing requirement. The explosion-proof ventilation systems are strengthened to ensure that it can go through the harmful gas strata smoothly and safely. The self-developed intelligent tunneling control system and all-round monitoring and warning system are equipped to realize intelligent tunneling.

Upon the completion of the tunnel, it will not only achieve that the high-speed train can travel under the river with no need to reduce the speed, but also become an important intercity passageway for the Yangtze River Delta urban agglomeration.