兰渝铁路桃树坪隧道为Ⅰ级铁路双线隧道,穿越上第三系富水粉细砂地层,由于粉细砂层成岩作用差,遇水呈流塑状自稳性变差,隧道施工困难,极易发生塌方,塌方处治难度极大,安全风险极高.为解决富水粉细砂层隧道塌方后砂层松散、流动性强、无自稳、塌方处治困难等一系列问题,确保安全快速通过塌方段,以桃树坪隧道3#斜井正洞塌方处治为工程实例,就如何采用"真空降水+双层大管棚+小管棚+双侧壁法"有效处治富水粉细砂层隧道塌方进行详细论述与总结,成功案例可为类似工程施工提供一定的技术参考和经验借鉴.%Taoshuping tunnel,a Grade Ⅰ double-line railway tunnel,crosses tertiary water-rich fine-sand strata. As a result of the poor diagenesis of fine-sand strata and bad self-stability when mixing water, the tunnel construction is difficult and the easily encountering of collapse is difficult to treat. In order to deal with the above-mentioned problems and guarantee rapid construction of the Taoshuping #3 Tunnel, the technology of "vacuum dewatering+double-layer large pipe roof+small pipe roof+double-side drift method" is discussed and summarized to provide reference for similar projects in the future.
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