高水头作用下深埋长大隧洞围岩稳定的数值模拟研究

Numerical Simulation Study on Surrounding Rock Stability under High Water Pressure in Long Deep-buried Tunnel

在深埋隧洞开挖过程中,不可避免地将会遇到高水压和高应力,以及这两个因素所控制和诱发的问题,因此分析水压作用对围岩稳定性的影响具有重要意义。针对研究高水压对深埋隧洞围岩稳定性的影响,结合锦屏二级水电站引水隧洞的实例采用FLAC3D软件进行数值模拟。通过计算不同水压力条件下的围岩最大变形量,建立围岩最大变形量与水压力之间的关系,求解临界水压力。当岩体强度满足一定条件时,只要水压力小于临界水压力,就可忽略水压对围岩稳定性的影响。结果表明:对于白山组大理岩Ⅱ类围岩可忽略水压作用;而对于白山组大理岩Ⅲ类围岩,高水压对其影响比较大,出现严重变形,需做支护处理。

Inevitably,high pressure groundwater,upland stress and the problems controlled and induced by the two factors will come out during deep-buried tunnel excavation,so the analysis of influence of water pressure on surrounding rock stability will be of high significance.In order to study the influence,FLAC3 D is used for the numerical simulation analysis of Jinping Ⅱ Hydropower Station.Through calculation of the maximum deformation of the surrounding rock under different conditions of water stress,the relationship between the deformation of surrounding rock and the water pressure is established and the critical water pressure is solved.When the rock strength meets some conditions,the water pressure influence on the stability of surrounding rock can be ignored if the water pressure is less than the critical water pressure.The results of numerical simulation analysis show that the surrounding rock of marble Ⅱ can be ignored and high water pressure has a great influence on the surrounding rock of marble Ⅲ which suffers a severe deformation and it is necessary to support.