Study On Seepage Field And Lining’s Treatment For Water Pressure Of Tunnels In Water-Enriched Region

Considering with the influence of faults, karsts and high water pressure, hydrogeologic condition becomes complicated frequently when the tunnel across water-enriched region and groundwater is an inevitable problem for engineers. Mainly through numerical simulation and based on the new Huayingshan tunnel of Nandaliang Highway which connects Nanchong and Dazhu and Liangping, this paper is aimed at seepage field and water pressure of tunnel lining under controlled drainage system. The main results are as follows:(1)Based on the similarity of basic theory, initial condition, differential control equation and boundary condition between temperature field and seepage field, replaceable parameters are clear. In different construction stages, water pressure of tunnel lining has been work out under temperature analogy method and analytical solution which shows the feasibility and suitability of temperature analogy method.(2)The seepage field’s characteristic and supporting structure’s water pressure distribution of tunnels under controlled drainage system have been dissected by adopting temperature analogy method. Sewerage system’s and grouting parameters’ impact on mechanical characteristics of tunnel lining have been studied to provide reasonable parameters for the tunnels in water-enriched region.(3)In order to simplify composite lining, the paper has proposed equivalent seepage coefficient by equality of invert’s water pressure. With the transformation law of lining’s water pressure across faults analyzed, the paper has put forward optimizing the transition arc and invert’s radius whose ratio reflects tunnel lining’s resistance to water pressure. In addition treatment measures of tunnel lining have been set out under high water pressure.The research has provided an effective and theoretical way to solve the problem of the groundwater’s prevention and control. Groundwater’s controlled drainage is able to ensure construction’s safety and reduces the impact on the environment in water-enriched region, and also provides a reference for tunnel’s design and construction in other areas.