隧道水平岩层变形破坏机制的模拟研究

Simulation Study on the Deformation and Failure Mechanism of Level Rock in Tunnels

在对隧道围岩体的物质组成和结构力学特征分析的基础上,文章定性分析了某隧道围岩体的变形破坏机制;采用底摩擦试验方法,确定了合理的试验参数,并依据现场岩层层面和节理产状建立了室内地质模型。试验结果表明,围岩体变形可分为三阶段,即弯曲内鼓、拉裂和折断塌落阶段。最后采用2D离散元程序对该隧道开挖过程进行了数值模拟,结果与室内模型试验结果基本吻合,可见采用室内模型试验和离散元数值模拟,能够较好地预测隧道在开挖过程中围岩体的变形特性。

Based on an analysis of the material composition and structural mechanical characteristics of tunnel surrounding rock, the deformation and failure mechanism of the surrounding rock in a certain tunnel was qualitatively analyzed, the rational test parameters for the base contact friction experiment were determined and an indoor geological model was established according to in-situ stratum bedding and joint occurrences, with the results indicating that deformation of the surrounding rock can be divided into three phases, i.e., bending and inward heaving, tensile cracking, and breaking and collapsing. This was verified for the tunnelling process using a2D-UDEC numerical simulation, with the results being basically consistent with that of the laboratory model experiment. Thus it is clear that prediction of the deformation behavior of surrounding rock during tunnelling is possible by adopting this indoor model experiment and UDEC numerical simulation.