In order to solve the problem of longitudinal non-uniform deformation and stress of shield tunnel under additional external forces in the engineering of immediate shield tunnel or shield tunnel piercing through pile foundation,a new calculation model for longitudinal deformation of shield tunnel is proposed by using a computational analytic method to consider shield tunnel as Timoshenkobeam placed on Pasternak two-parameter foundation,and introduce the modified equivalent continuum model and transfer matrix method,which is verified by the method of laboratory model test.The results show that in the model test,under the combined action of concentrated load and confining pressure,during the whole elastic deformation stage of the tunnel,the convergence deformation of each ring segment,the vertical displacement of the arch crown and arch bottom,and the misalignment of the circumferential seam all increase approximately linearly with the increase of concentrated load,and they are distributed symmetrically along the longitudinal direction with the concentrated load as the center,whose deformation trend is the same as the calculation result.With the two methods,the maximum relative error of circumferential seam misalignment is only 8.75％.The results obtained by two methods are basically consistent in terms of distribution characteristics and magnitude,which verifies the feasibility of the calculation model.The model can reflect the shear action between soil springs,the influence of convergence deformation on longitudinal deformation stiffness of tunnel and discontinuity of joint.It can predict and analyze the longitudinal deformation and internal force of shield tunnel,and provide theoretical guidance for the safety evaluation of the existing shield tunnel in the immediate shield tunnel engineering.
关键词
盾构隧道/铁摩辛柯梁/Pasternak双参数地基模型/纵向变形
Key words
Shield tunnel/Timoshenko beam/Pasternak two-parameter foundation model/Longitudinal deformation
维普
万方数据