北京轨道交通大兴机场线盾构选型研究

北京轨道交通大兴机场线于2019年通车运营,采用市域D型车实现草桥—大兴机场20 min的通达目标,以160 km/h的运行时速填补城市轨道交通高速领域的技术空白。工程定位高、沿线建设环境复杂、工期紧张,没有既有规范及建设经验可以参照,致使盾构隧道结构选型、标准确定难度大。分析研究不同结构断面形式盾构外径及内径的影响因素,从而确定大兴机场线盾构可选的断面型式,并据此进行造价、工期及安全比选。最终确定大兴机场线盾构隧道采用7.9 m内径、8.8 m外径的单洞单线结构,盾构机采用土压平衡盾构机。

Shield Type Selection for Beijing Daxing Airport Express

The Beijing Daxing Airport Express has been operating since September 26, 2019, using the urban D-type vehicle to maintain the 20-min travel time between Caoqiao Station and Daxing Airport Station. With its traveling speed of approximately 160 km/h, this vehicle has filled the gap in terms of speed in the field of urban railway transportation. The Daxing Airport Express is a high-end new project with complicate construction environments. Moreover, the schedule of the project is tight and there are no existing engineering norms and practice to follow. As are result, it is difficult to decide the shield tunneling structures and standards. In general, this study analyzes the factors that influence the choice of the external and internal diameters of shield tunneling with different cross-sections to devise plans, as well as schemes considering cost, schedule, and safety. The final choice is to use a single-hole and single-line tunnel structure with inner and outer diameters of 7.9 and 8.8 m, respectively. Moreover, for tunnel boring, the use of an earth pressure balance machine is suggested.