廖家荣,王 凯,张奎涛,陈怿旸

CRD法原理是通过分部开挖，将大断面隧道转化为小断面洞室开挖，以减小对周边围岩的扰动，同时单个小洞室均可自行封闭成环，加快了围岩的稳定时间，减小了上部岩体的沉降，提高了隧道施工的安全性。浅埋偏压软土隧道施工风险高于常规水平隧道，常采用交叉中隔壁法(CRD法)等安全性较高的工法进行开挖。在浅埋偏压地段，围压压力和CRD工法均具有非对称性特征，本文建立三维数值仿真模型，以优化CRD法施工顺序，降低偏压隧道施工安全风险。结果表明，先开挖深埋一侧，无论是围岩稳定性还是初期支护结构受力均更为有利，但先开挖浅埋一侧也能满足工程安全控制要求。因此确立了浅埋偏压软土隧道CRD法应先开挖深埋一侧导坑的原则，并在此基础上进一步提出了减小初期支护整体沉降的关键控制措施。

隧道；浅埋偏压；CRD法；开挖顺序；控制措施

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