Study On Impact Of Seepage And Stress Fields Coupling On Surrounding Rock And Lining Of Tunnel

The mechanism and mathematical model of seepage and stress fields coupling, by theback-analysis theory of surrounding rock parameter and applications are researched in thepaper, based on the Baishan and Huilongshan mountain tunnel engineering of GuangdongShaogan Expressway, using the genetic algorithm combining with the water pressuremonitoring data of Shaogan expressway construction, infiltration coefficient of the tunnel siteof the rock by the back analysis is being calculated, the strutural properties of cross sections,considered optimal design Shaogan expressway tunnel section and the standard design tunnelsection, are calculated based on the finite element models and the analysis software ABAQUSuser subroutine, the seepage field and stress field coupled constitutive relation subroutine foranalysis of the mechanical properties of surrounding rock and the lining under seepage andstress fields coupling and consolidation are considered respectively, with taken two crosssections into account, finally all cross section safety factor for the optimum design section andthe standard design one are calculated to assess the safety, by the use of improved first ordersecond moment method in the reliability theory, to calculate the reliability of the tunnelsection of various design and the analysis results obtained are as follows :(1) The safety or reliability for the optimal section design are better than that of standardones, in particular in the case of withstanding water pressure load, the reliability and safetyfactor for optimmal tunnel sections are improved greatly in the worst combination area ofinternal forces, on the other hand, these parameters on other parts of the tunnel are alsoincreased and improved significantly.(2) The coupled analysis results considering the seepage field and stress field shows thatthe porosity, permeability, damage value are constantly changing with the different stress statein the process of tunnel construction, and the calculation results ih the paper are verified bythe practice.