高应力区隧道围岩变形破坏的数值模拟及物理模拟研究

Numerical simulation on deformation and failure of surrounding rock in high in-situ stress and its verification in physical model

隧道失稳和维护困难是高地应力隧道的普遍问题,对隧道的支护设计提出了更高的要求。研究从地下工程岩体应力环境变化和岩体强度变化的角度探讨了高应力隧道围岩的变形破坏机制。根据重庆某深埋隧道围岩实际情况,运用FLAC3D三维显式有限差分法分析软件,建立了摩尔-库仑剪破坏与拉破坏复合的应变软化模型。通过隧道的三维数值计算,分析了高应力环境下隧道周边塑性区分布、应力场、位移场等的分布特点,得到了高应力隧道围岩在高地应力环境下的破坏规律。通过物理模型验证了高应力隧道围岩的破坏特点,并进行了超载试验,将其与数值模拟进行对比,进一步验证了所建数值模型的科学性。

Structure and support failures of tunnels are common problems for deep tunnels in high in-situ stress rock masses and they have more requirement on support designing. Based on the alteration of surrounding pressure and the strength of engineering rock mass,the mechanism of deformation and failure of surrounding rocks of the tunnel constructed in high in-situ stress rock masses is studied. According to rock character of a certain tunnel of Chongqing,the Mohr-Coulomb criterion with tension cut-off strain-softening model is adopted,a three-dimensional nonlinear simulation for it has been carried out. The distribution of plastic zones,tensile stress zones,displacements and the progressive failure of the surrounding rock is analyzed,the failure law of the surrounding rock in high in-situ stress. For application in site,the physical model results is used and the results agree with the numerical model.