Mechanical Analysis Of Surrounding Rock And Support In The Earth-rock Interface Stratum Of Tunnel

Along with the rapid economic development of western China,the corresponding transportation infrastructure has also been greatly developed.As an important part of traffic facilities,tunnel is widely used in engineering construction of crossing loess stratum.However,due to the complex geological condition of loess stratum,tunnel construction often encountered the bad geological condition of soil and stone boundary.Uneven earth-rock boundary strata of the hard and soft surrounding rock,the mechanical properties of big differences,which were liable to occur during the tunnel construction process inhomogeneous deformation,bias,and the problem of collapse so it is necessary for earth-rock boundary strata system studies the characteristics of deformation and stress in the tunnel construction.This paper relies on the actual engineering of the Kuandaoshan tunnel,uses the on-site monitoring data to analyze the tunnel's disturbed deformation of the surrounding rock and soil,and compares the calculated values with the measured values on site to study the specific distribution of surrounding rock pressure.On this basis,the finite element software was used to study the influence of the interface of earth and stone under different conditions on the tunnel construction,and the specific construction plan of Kuandaoshan was demonstrated and analyzed.The details are as follows:(1)Based on the on-site monitoring work of the kuandaoshan tunnel,the monitoring data of the dome settlement and surrounding convergence are analyzed,and then the deformation characteristics of the surrounding rock of the earth-rock boundary are summarized,and secondary lining is given.The recommended time for the operating time.(2)the pressure distribution between surrounding rock,primary support and secondary lining is analyzed in combination with the field measured values of surrounding rock pressure in the kuandaoshan tunnel.At the same time,the applicability of the calculation formula of surrounding rock pressure is summarized by comparing and analyzing the calculation formulas of each calculation theory and the measured values of surrounding rock pressure field.(3)Set up a two-dimensional stratigraphic model of the kuandaoshan tunnel to study the effects of the four factors of the interface dip,the ratio of the earth and stone area,the stiffness ratio,and the depth of the tunnel on the stress of the tunnel supporting structure and the deformation of the surrounding rock,and then analyze the results based on the model.Give corresponding construction advice.(4)Combining the construction scheme of the Kuandaoshan Tunnel,a three-dimensional model was established using numerical simulation software,and the deformation law of the surrounding rock under the boundary condition of the earth-rock boundary was analyzed to demonstrate the feasibility of the above-mentioned construction scheme.