Wednesday, February 15th, 2017 saw the commencement of TBM tunneling works of the 2.688km long tunnel for the Meichuang Section of Shenzhen Metro Line 10.
The tunnel is to cross Shenzhen Metro Line 6 and Xiamen-Shenzhen Railway. The minimum overburden is 15m and the smallest curve radius is 400m. The TBM, a 6.5m dia. Double Shield Hard Rock TBM designed and manufactured by CREG, will have to excavate through slightly to moderately weathered granite with high UCS. Meanwhile there also exist F1 and F2 fault and fractured zones along the line.
To cope with the complicated geotechnical conditions, CREG has integrated Wirth technology to develop tailor-made designs for the Double Shield TBM (6.5m diameter, 135m long). The machine is equipped with 19” disc cutters to ensure high rock-breaking efficiency. Hardox plates are applied to areas vulnerable to frequent and serious wear. Anti-clogging designs are also incorporated to guarantee the machine’s continuing tunneling in varying conditions.
Compared to conventional tunneling methods like blast and drilling, TBM lowers the construction risk significantly. Moreover, it saves not only time and cost but also environment. That’s why it is now playing an increasingly important role in modern civilized construction.