三峡永久船闸高边坡开挖三维离散元数值模拟

3-D simulation of the excavation of high steep slope of Three-Gorges permanent lock by distinct element method

采用面-面接触的三维离散元刚性块体模型,从实测节理面中取出其中的三组,按照其倾向、倾角和节理间距将三峡永久船闸未开挖的区域划分为105个离散单元,通过施加力边界条件,给出了与实测初始地应力场接近的数值模拟结果;然后,分4步模拟了永久船闸的开挖过程。计算结果表明:开挖过程会引起节理面出现张开趋势,个别岩体还会沿着节理面滑移。岩体位移的不对称现象较为自然地说明了由节理引起的岩体各向异性特征。

According to plane contact model of 3-D distinct element method (DEM) and three sets of joints obtained from site measurement, 100000 blocks were used to simulate the Three-Gorges permanent lock high steep slope area. The computation consists of the simulation of the initial stress by acting force boundary condition and the process of excavation. Obtained initial stress field is consistent with the measurement data. The process of excavation was simulated by four-step excavation. The results show that the process of excavation can stir expansion of joint layers and thus some blocks may slide along joints. The displacement of rock is asymmetry and this fact naturally illustrates the anisotropic character of rock mass.