基于土层重力效应的近邻双孔隧道地层位移计算和扰动分区

Ground displacement calculation and disturbance zoning of adjacent twin-bore tunnel based on gravity effect of soil layers

为分析近邻双孔隧道施工的相互影响,利用复变函数和Schwarz交替法求解基于土层重力效应且洞室发生收敛变形的地层位移解析函数,通过设置位移约束点对地层位移进行修正,最终获得了土层重力效应下近邻双孔隧道开挖的解析模型。采用该解析模型分析了迭代次数、位移约束及洞室水平变形对地层位移的影响规律。结果表明:当迭代次数为2时,计算结果已满足精度要求;设置竖向位移约束边界使地表相对沉降曲线整体发生向下偏移,左侧水平位移约束边界则使相对水平变形向左侧发生一定量的偏移;随着洞室水平变形系数的增大,地层相对竖向变形随之增大而相对水平变形却随之减小,且对两者的影响程度不一致。基于地层位移判别准则,获得了基于几何近接度和埋深比的双孔隧道的强、弱、无影响分区。

To analyze the mutual influence of adjacent twin-bore tunnel’s construction,complex function and Schwarz alternation method were used to solve the analytical function of ground displacement based on the gravity effect of soil layers and the convergent deformation of tunnel chamber,and the ground displacement was corrected by setting displacement constraints,so that an analytical model of adjacent twin-bore tunnel under the gravity effect of soil layers was finally obtained.Based on the model mentioned above,this study analyzed the influence of iteration number,displacement binding,and horizontal chamber deformation on the strata displacement,and the results shows that the calculation meets the accuracy requirements with iteration number of 2.It should be noted that by comparing the results corrected by displacement with those without the displacement correction,setting the boundary condition of vertical displacement makes the relative displacement curve of ground surface shifted downward as a whole,and the left horizontal displacement boundary condition can make horizontal deformation shift leftward at a certain amount.With the increase of chamber’s horizontal deformation coefficient,the relative vertical deformation of strata will increase while the relative horizontal deformation will decrease,and the effects on them are different.Based on the criterion of ground displacement,the strong,weak and no influence zones of the twin-core tunnel with geometric proximity and buried depth ratio are obtained.