Elasto-plastic Analysis Of Surrounding Rock And Optimization Of Construction For Tunnels Under Seepage Effects

With the needs of the development of traffic, the scale of tunnel engineering development is larger and larger, the tunnel will inevitably be through the shallow berried region with rich underground water in the process of building, and the series of engineering problems caused by the groundwater are also increasingly paid much more attention to by human. Therefore, it is particularly important to research the shallow and seepage tunnel.In the engineering background of Hengchaji railway extra-long tunnel—Eling Tunnel, this paper has analyzed and researched reinforcement measures and reinforcement effects of rock mass in the shallow and seepage tunnel detailedly. Based on the analysis of the research achievements on the fluid-structure coupling, rock mass elastic-plastic and surrounding rock reinforcements, the thesis has mainly completed the following aspects:1). Elastoplastic analyzing on the rock mass of circular tunnel, and taking into the effect of seepage account, the elastoplastic solution of the surrounding rock stress and displace of rock mass in the circular tunnel have been derived based on the nonlinear yield criterion, using mathematical calculation software for its related numerical solution, and the influence curves of surrounding rock stress and radius of plastic zone have been obtained finally by qualitative analysis for single different affecting factors.2). Numerical simulation of construction process on Eling tunnel by the three dimensional finite difference software, the seepage field, stress field and displacement field of shallow and seepage tunnel on taking into the effect of seepage account have been analyzed emphatically.3).The effects of surrounding rock reinforcement and the influence of surrounding rock reinforcement measures on surrounding rock stability after excavation of the tunnel have been researched, and the influence of surrounding rock stability have been compared between six different surrounding rock reinforcements by using the three dimensional finite difference software.4). Based on the site monitoring measurement in Eling Tunnel, the influence of specific construction process on tunnel surrounding rock has been studied, especially the vault settlement, the level convergence, the surrounding rock pressure and the steel liner plate stress.