The middle section is a key and difficult construction point along the entire Shenzhen-Shantou High-Speed Railway. The tunnel is 10,307 meters long, with a single tunnel and double tracks. It is designed for a speed of 350 kilometers per hour and constructed by using TBM and NATM methods. The TBM section is 3,685 meters long, with a maximum overburden of 97 meters and a maximum rock layer strength of 83 Mpa. During the construction, it is necessary to undercross rivers, reservoirs, ponds, railways, expressways and so on multiple times, and pass through two fractured zones. The geological conditions are poor, with water-rich sections and well-developed stratum fissures, which puts forward high requirements for the pressure-bearing capacity and equipment performance of the TBM. The TBM needs to enter the tunnel through an inclined shaft, be assembled, pushed and launched in the cave room of the mountain, and finally be received and towed back and disassembled inside the tunnel. This is the first case in China.
In response to the key and difficult points of the project construction, CRCHI developed the “Longgang No. 2” TBM. It adopts a heavy-duty composite cutterhead and is equipped with intelligent tunneling assistance systems such as advanced geological prediction, cutterhead and cutter condition monitoring, and stratum feature perception. Equipped with a telescopic camera and a high-pressure flushing system to prevent mud cakes from forming on the cutterhead. Jaw crushers and secondary double-toothed roller stone crushers are Installed to enhance the efficiency of rock breaking and muck discharge. By means of the ground remote operating system, a dual-control switching between surface-ground and underground can be achieved.
The Shenzhen-Shantou High-Speed Railway started construction in January 2021, with a bridge-tunnel ratio as high as 92.6%. Currently, it is in key stages of TBM tunneling construction. After its completion, it will take only one hour to reach the urban agglomeration in eastern Guangdong, and five hours to reach the urban agglomeration in the Yangtze River Delta from Shenzhen via the Shenzhen-Shantou High-Speed Railway. This will play a significant role in accelerating the construction of a high-speed railway along the coast, optimizing the external railway channels of the Shenzhen hub, and promoting the development of the Shenzhen-Shantou Special Cooperation Zone.
