富水砂卵石地层大直径盾构下穿既有运营隧道施工技术

Construction Technology of Large-diameter Shield Underpassing Existing Operating Tunnel in Water-rich Sand and Cobble Strata

随着城市轨道交通的高速发展,新建地铁线路穿越既有运营线路越来越多,为了减小对既有运营线路的影响,需要针对性进行加固处理。以成都地铁19号线双流机场—龙桥路站区间下穿既有运营3号线为工程背景,对加固施工进行了深入研究,采用超前管棚加固(管棚穿入固结体内)、地面预注浆加固相结合的处理方案。由于地质条件的复杂性、砂卵石地层容易受扰动、施工的不确定性、既有运营隧道对变形要求极高等特点,通过采用先进施工工艺、精细化施工,确保了盾构施工及运营线路的安全。

With the rapid development of urban rail transit, more and more new subway lines cross existing operating lines. In order to reduce the impact on existing operating lines, it is necessary to carry out targeted reinforcement treatment. Based on the engineering background of Shuangliu Airport-Longqiao Road Station of Chengdu Metro Line 19 under-crossing the existing Line 3, the reinforcement construction was studied in depth, and the treatment scheme of combining the advanced pipe roof reinforcement(pipe roof penetrating into the consolidated body) with the ground pre-grouting reinforcement was adopted. In accordance with the complexity of geological conditions, the disturbance of sandy pebble stratum, the uncertainty of construction, and the extremely high deformation requirements of existing operating tunnels, the safety of shield construction and operating lines has been ensured by adopting advanced and refined construction technology.