On August 22, the Left Line of Shasan Station of Shenzhen Metro Line 12 Phase II Project was completed by adopting “Dayu · Tunneling Machine” (CREC 1179), the world’s largest cross-section combined rectangular pipe-jacking shield machine jointly developed by China Railway Engineering Equipment Group Co., Ltd. (CREG) under CRHIC and other units, which blazes a trail in super-large cross-section mechanical excavation of metro station in the world.

The 208.4m long Shasan Station has two floors underground, with an island platform. The pipe jacking section is 70m in length, and the finished station section size is 22.6m*13.5m, equivalent to 3/4 of the sectional area of a standard basketball course. To adapt to such complex geological conditions as abundant ground water and soft upper soil and hard lower soil, the R&D team of CREG exclusively developed the “Dayu · Tunneling Machine” rectangular pipe-jacking shield machine tailored for the project of Shenzhen Metro Line 12 Shasan Station. Measuring 11.29 meters wide and 13.55 meters tall, which is equivalent to the height of a four-story building, the equipment consists of the upper and lower units, set with multiple cutters. Based on the coordinated control of several screw conveyors, shallow-overburden, large cross-section and zero-clearance excavation is realized with the aid of micro-step excavation technology and position measurement & control technology, thus effectively guaranteeing safe, high-quality and efficient construction of the project.

Since the “Dayu ·Tunneling Machine” was put into operation, under the joint efforts of all parties involved in the construction, the constructor has solved the problems such as low assembly efficiency of combined sections, carrying-soil effect and position control, and successfully excavated by 70m of the Left Line despite the complicated site geological conditions. During the excavation, the equipment operation is stable, with position controllable and without abnormal ground surface settlement, thus achieving good expected effect.