含节理岩体深埋引水隧洞围岩稳定性分析及优化设计研究

Stability Analysis and Optimization Design of Surrounding Rock of Deep-Buried Diversion Tunnel with Jointed Rock Mass

针对某水电站引水隧洞实际地质情况,采用离散单元法,深入研究了含节理岩体深埋引水隧洞初始应力、开挖锚喷支护及运行期工况下围岩应力分布情况及变形特点。研究成果表明:洞室开挖后顶拱及边墙部位顺节理方向变形突出,受围岩拱效应的影响底板出现较大位移,且局部存在应力集中现象;塑性区及锚杆拉应力呈明显不对称分布状态,节理对岩体整体稳定性影响效果明显。基于研究成果,结合施工过程中实时反馈的地质信息,提出了节理岩体中深埋引水隧洞围岩稳定动态反馈分析和支护优化设计方法,在应用于该工程实践的同时,对类似水电站引水隧洞衬砌结构优化为挂网锚喷支护设计具有一定的指导和参考作用。

In view of the actual geological conditions of diversion tunnel of a hydropower station,the discrete element method is used to study the initial stress of deep-buried diversion tunnel with jointed rock mass,the stress distribution and deformation characteristics of surrounding rock under excavation,bolting and shotcreting and operation conditions.The research results show that the deformation of the top arch and the side wall is prominent along the joint direction after the excavation of the cavern,and the bottom plate has a large displacement affected by the arch effect of the surrounding rock,and there is a local stress concentration phenomenon.The tensile stress of plastic zone and bolt is obviously asymmetric distribution,and the joint has obvious effect on the overall stability of rock mass.Based on the research results,combined with the real-time feedback geological information in the construction process,the dynamic feedback analysis and support optimization design method of surrounding rock stability of deep diversion tunnel in jointed rock mass are proposed,which is applied to the engineering practice.At the same time,it has a certain guiding and reference function for the optimization of similar hydropower station diversion tunnel lining structure to the design of hanging anchor shotcrete.