复杂地质条件下地下洞室群围岩稳定性研究

Study on the Stability of Surrounding Rock Under Complex Geological Conditions in Underground Cavern Group

以某水电站右岸溢洪洞及放空洞为研究对象,结合溢洪洞及放空洞围岩的工程地质条件和工程设计方案,建立体现地质构造及地形地貌的FLAC^(3D)仿真模型,密切结合拟定的开挖方案,研究地下洞室开挖后围岩的二次应力场及变形场的分布规律及破坏特征。结果表明,地下洞室群开挖后圉岩向临空面方向发生回弹变形,总体上表现出整个工程体系外围临空面位移较小而内部临空面位移较大的特征;位移总量最大的是顶拱位置,其次是底板位置,再次是左右边墙;受山体地形地貌及地质构造的影响,地下洞室洞轴线方向的应力及变形变化相对较大。

In this paper, taking the spillway tunnel and emptying tunnel at the right bank dam of a hydropower station located in northwest China as the research object, combined with the surrounding rock of engineering geological conditions and engineering design scheme in spillway tunnel and emptying tunnel, established the cavern simulation model that reflected the geological structure and the topography of the underground cavern group with the FLAC3D. The secondary stress field, the distribution of deformation and destruction features of surrounding rock after excavation were studied according to the excavation engineering of underground cavern group. The results show that the surrounding rock mass deforming toward surface direction springback deformation occurs, which shows the characteristic with whole project system overall international airport peripheral surface displacement smaller but internal opening displacement bigger, displacement amount of the largest is the crown of position, the second is the bottom position and the last is right and left sidewalls. Mountain landform and geological structure, the influence of the stress and deformation of underground caverns axis direction change relatively larger.