| The construction of deep-buried high-water tunnel is an important link in the development of modern cities.The construction condition of this kind of tunnel is very complicated and grouting is often used to reinforce rock mass on the basis of support to ensure the safety of construction.According to the theory of plane elasticity,the problem of the tunnel construction grouting reinforcement layer and the supporting role can be converted into the plane multiply connected hole to analyze.The complex function analysis method can effectively solve different pass and complicated boundary conditions and working conditions on surrounding rock stress and displacement,which can be interpreted for the same problem.In this paper,the complex function method is used to analyze the mechanics of the deep buried high water tunnel structure under the action of grouting,and the analytical forms of stress and displacement on the surrounding rock of the tunnel are calculated,which provides a favorable basis for the construction,reinforcement and support design of the tunnel.The main research contents and conclusions are as follows :(1)According to the theory of plane elasticity and tunnel mechanics,the initial stress field of deep buried tunnel structure under the influence of high water level and high in-situ stress is obtained.(2)By using conformal transformation method,the analysis problem of deep buried tunnel with grouting layer and support layer is transformed into the problem of solving multi-connected region in infinite domain plane.Under the action of initial stress field and internal and external load,a mechanical model is established for solving the analytical solution of stress and displacement of any hole.The model has universal application.(3)According to the power series solution method,the analytic function and mapping function are expanded into series form,and the linear equations are established to solve the undetermined coefficients of the number of terms in the analytic function through boundary conditions,and then the mathematical form of the analytic function and the analytical solution form of stress and displacement are obtained.(4)Taking straight wall semicircle arch tunnel as an example,the optimization algorithm was used to solve the mapping function coefficient,and the analytical results were obtained according to the accuracy requirements.The numerical results of tunnel stress and displacement were obtained by ANSYS software,and compared with the analytical results.The results show that the analytical results satisfy the boundary conditions.Except for the stress and displacement at the stress concentration position,the other positions are in good agreement with the numerical method.(5)Taking Mawan tunnel project in Shenzhen as the background,the mechanical analysis of shield tunnel in sea section is carried out by analytical method,and the influence of different grouting layer thickness on the stress and displacement of tunnel structure is discussed.The results show that within 5 times of tunnel radius,the larger the grouting thickness is,the smaller the stress of supporting layer is,and the better the mechanical properties of surrounding rock are.In the range of thickness ratio from 0.1 to 0.6,the greater the grouting thickness,the smaller the change of tunnel structure displacement,but beyond this range,the effect is not significant. |
