锦屏二级水电站引水隧洞长期稳定性数值分析

针对锦屏II水电站深埋引水隧洞高地应力、强渗透压的复杂赋存环境及硬脆性岩体的特点，采用凝聚力弱化-摩擦强化（CWFS）模型反映岩体的脆塑性变形特点。采用黏弹性模型反映其黏性变形规律，基于现场的位移监测资料，通过遗传规划和粒子群算法的流变模型及参数识别方法得到黏弹脆塑性流变模型及其参数，利用大型岩土工程分析软件FLAC3D，模拟了隧洞群岩体的流变力学行为、喷锚支护型式及其与围岩相互作用机制以及工程结构体在高渗透压下的流固耦合效应。通过模拟结果的分析，采用位移、位移速率、应力、破坏接近度及支护结构的受力状况等状态信息的综合集成分析方法，对此工程围岩及结构体在复杂赋存环境中的长期稳定性状态进行了评价，并论证了现有设计方案的合理性，为指导工程设计和施工起到重要的作用。

Numerical analysis of the long-term stability of the seepage tunnel in Jinping II Hydropower Station

The four seepage tunnels in Jinping II Hydropower Station are buried in the hard brittle rockmass. The complex geological condition including high stress induced by great depth and high seepage pressure will bring about many engineering problems, especially the long term stability problem. In order to reflect the character of the visco-plastic deformation, the combinative models of cohesion weakening-friction strengthening model and the visco-elastic model are introduced in this study. And based on the in-situ displacement monitoring data, the visco-elasto-plastic model and its parameters are obtained by the intelligent method based on GP and PSO methods. The rheological mechanic characters of the surrounding rockmass in the seepage tunnels are simulated by using FLAC3D. At the same time, this program can also simulate the mechanism between the sprayed concrete, rock bolts and rockmass and the coupling effect of fluid and solid under the high seepage pressures on the structures. Through the analysis of the calculated results, the long term stability of the tunnels is estimated by using the integrating method of multi-index including displacement, displacement velocity, stress, failure approach index and the internal force in the support structures and soon. The results are of importance to the design and construction of this project.