基于离散单元法的软岩隧道施工过程数值模拟与围岩变形分析

以震后重建工程S302线大马庄隧道为工程实例,采用通用离散元程序UDEC建立平面弹塑性模型,进行了隧道施工过程数值模拟,得到了某一指定横断面上各监控点的全断面开挖围岩变形量及其变化规律,并与实际现场量测数据对比,发现模型计算所得量值与实测量值能较好地吻合。同时采用UDEC程序对该断面进行了台阶法开挖模拟,模拟结果表明分部开挖可有效减小拱顶沉降量和水平位移量,抑制底拱部隆起,且围岩变形主要发生在上台阶开挖阶段,及早闭合临时仰拱可有效减少围岩变形。离散元程序可根据现场情况模拟围岩变形规律,并可结合实测数据对施工提出修改和指导意见。

Soft Rock Tunnel Construction Process Simulation and Rock Deformation Analysis Based on Discrete Element Method

Based on Damazhuang Tunnel project,a plane plastic model is built using discrete element program UDEC,to simulate rock tunnel construction process and get the rock deformation and variation of control points in the given cross section.It is found that model calculated values can be good fit with mea-sured date after a comparison.Then using the program UDEC the step excavation is simulated,showing that step excavation can effectively reduce the crown settlement,horizontal displacement and control the uplift of arch bottom.The main deformation occurs in the up step excavation stage,so early closing the temporary invert can reduce rock deformation.Discrete element program UDEC can simulate tunnel excavation according to the scene;propose and guidance are given to the construction combined with the mea-sured date.