On April 28, CCCCTH launched two DTSES TBMs,which were named “Xueshan” and “Xuelian” respectively, atChangshu Base of CCCCTH.The two DTSES TBMs represent first of their kind in the world and are going to serve the construction of TianshanShengli Tunnel of Wuyu Expressway in Xinjiang Uygur Autonomous Region, the world’s longest expressway tunnel and also an important project under the framework of the Belt and RoadInitiative(BRI). The two TBMs willthen undertake the task of opening up a transportation route between the north and south of TianshanMountainand promoting the rapid development of the BRI. Faced with the impact of the novel coronavirus pneumonia epidemic, CCCCTH has taken strict epidemic prevention and control measures and at the same time promoted resumption of work and production. With all-out efforts to resumework and production for key projects in an orderly manner and continuous adjustmentfor and optimization ofthe production plan to ensure progress, the company has finally managed to producethe two TBMs as scheduled.
TianshanShengli Tunnel is a key project for Wuyu Expressway.With an overall length of 22.69km,the tunnel is by far the world’s longest expressway tunnel. It is located in a place characterized by high ground stress, coldness, high earthquake intensity, high altitude, and multiple fault zones. Given such extreme conditions, the TBMs are bound to meet many universal problems like excavation through large faults, fracture zones, and large deformation of soft rock, rock burst, slurry and water gush and high ground stress. The earthquake intensity at the tunnel site is VIII degree, while the maximum water inflow at the site is about 29,000 m3/day,and the high-pressure water inflow pressure can reach 4 MPa (equivalent to water pressure produced by 400 meters of water).
In view of many problems that are likelyto be encountered during the construction, CCCCTH became the first to propose the concept of DTSES, and has already put it into practice in a creative manner. The DTSES TBM with two excavation modes and three support modes has been developed to cope with the complex geological conditions, and overcome some common problems for open-type TBMs like failure to propel due to the gripper’s slip, excess work for support and inability to clearing muck. Thus, safe, green, rapid and efficient excavation through complex geological conditions (great deformation, intense rock burst and multiple fault zones) can be ensured. These two novel-type TBMs feature a high degree of automation, strong geological adaptability and fast construction speed and can help ensure a good working environment on site and low labor intensity of workers.
These two φ8.43m TBMs are 282m long and weigh 2,000 tonnes. They have beendesigned to be used in open-type work mode (TSA mode) underfavorable rock conditions, extruded-concrete-lining support (TE mode)modein fracture zone, soft rock and rock-burst ground,and single-shield steel-segment supportmode (TS mode) inextreme fracture zone, area with large deformation of soft rock,and intense rock burst stratum section.