大断面浅埋隧道开挖施工技术及其数值模拟

Construction Techniques of Shallow and Large-section Tunnel and Its Numerical Simulation

京新高速苏木山隧道进洞浅埋段,开挖断面大,围岩软弱破碎,为V级围岩。为确保隧道开挖施工安全性和稳定性,选择合理的工法施工显得很有必要。针对该隧道的工程地质条件,提出采用双侧壁导坑法开挖施工,并基于三维有限元Plaxis-3D程序,对大断面浅埋隧道开挖施工进行数值模拟。研究结果表明:从隧道周围变形的情况来看,采用双侧壁导坑法开挖修建V级围岩条件下的三车道大跨度隧道是安全的;同时,数值模拟计算结果与现场实测结果是吻合一致的。

The entrance shallow-buried section of the Sumushan tunnel in Jingxin railway is a large section tunnel,and the surrounding rock is fractured and V level. In order to ensure the safety and stability of the tunnel excavation,it turns out to be of great necessity to select the proper construction method. Aimed at engineering geological condition of the tunnel,double-side-drift method is adopted during construction,besides,based on the three-dimensional finite element method Plaxis-3D,this paper numerically simulates the excavation of shallow-buried large section tunnel. The results shows that judging from the deformation around the tunnel,it is safe to excavate and construct the three lanes large-span tunnel in the V surrounding by using the double-side-drift method,at the same time,the result of numerical simulation is in accordance with the field measure.