基于渗流应力耦合的导流洞封堵期结构安全分析

Hydro-mechanical coupling model based safety analysis on structure safety during plugging of diversion tunnel

通过建立复杂三维渗流场模型,对导流洞整体三维渗流场特性进行分析;同时基于渗流—应力耦合模型,应用空气单元模拟导流洞渗流场分析中的排水孔效应,采用三维弹塑性非线性有限元法对导流隧洞开挖、支护、下闸蓄水及封堵期的围岩稳定及结构安全性进行了全面仿真计算分析。结果表明,采用空气单元可以有效模拟排水孔的排水效果;在顶拱围岩设置排水孔可有效降低洞周围岩的外水压力水头,改善支护结构的受力状况。

The characteristics of the entire 3-D seepage field of diversion tunnel are analyzed herein through the establishment of a complex 3-D seepage field model, meanwhile, based on hydro-mechanical coupling model, an overall simulation analysis, by application of the drain-hole effect in the analysis on the seepage field of diversion tunnel simulated by air element, on the exca- vation, supporting, gate closure and impoundment of diversion tunnel as well as its surrounding rock stability and structure safety during plugging is made with 3-D the elasto-plastic nonlinear finite element method. The results show that the drainage effect of drain hole can be effectively simulated with air element. Therefore, if drain holes are arranged within the surrounding rock of tunnel vault, the external water pressure head can be effectively lowered, and then the stress status of the supporting structure is to be improved as well.