盾构隧道下穿河道施工控制技术

Construction Technology of Shield Tunnel Passing Through River

盾构隧道下穿河道作为特殊的暗挖掘进工程,水下的复杂地质条件难以完全探查清楚,隧道施工风险高。施工中需要重点把握工作井基坑支护与防水、掌子面水土压力控制、水下盾构隧道管片防水、水下侧穿桥梁桩基及水下不良地质条件处治等施工要点,采取有效控制措施规避风险。在长沙地铁5号线盾构下穿浏阳河施工中,采取多项关键技术,在浅覆土条件下有效应对水下岩溶发育、侧穿桥梁桩基等施工风险,安全顺利下穿浏阳河,工程经验值得借鉴。

Shield tunnel construction underneath river is a special underground excavation project. The complicated geological conditions under water cannot be fully explored, which makes construction risk very high. The construction key points should be emphasized in the project, including the supporting and waterproof of the foundation pit, the control of the water and soil pressure in the tunnel face,the waterproof of the shield tunnel segments,the control of shield tunnel approach to bridge piles and the treatment of adverse geological conditions under water, and take effective control measures to avoid risks. During the construction of Changsha Metro Line 5 through Liuyang river, several effective techniques have been taken to deal with the construction risks of underwater karst development and shield tunnel approaching bridge piles under the condition of shallow overlying soil, and cross Liuyang river safely. The project experience is worthy of reference.