盾构隧道横向受力的通用解析计算方法研究

Study on Universal Analytical Method Calculating Transverse Stress of Shield Tunnel

在盾构近接工程中,隧道周围的土体荷载可能不再是半无限土体中的规则分布。从结构力学力法基本原理出发,通过对荷载分布的离散化处理,建立了一种通用的解析计算方法,可以计算任意土体荷载分布下隧道衬砌结构的内力和变形。为方便工程应用,借助于MATLAB编程,对3种土压力分布形式下的隧道内力和变形进行了程序化计算。结果表明:当侧向土压力为均匀分布和梯形分布时,衬砌环的内力和径向收敛位移差异较小,不超过10%;当侧向土压力为二次分布时,衬砌环的弯矩和剪力有所增加,轴力有所减小,横鸭蛋弯曲变形程度增强。

In the shield approaching works,the soil load surrounded is not regularly distributed in the semi-infinite soil mass,thus depending on the principle of force method in structural mechanics,an universal analytical method was established by means of discretization of load distribution so as to calculate the inner force and deformation of lining structure under any soil distribution;then under three kinds of soil pressure distribution,the inner force and deformation of tunnel was calculated by MATLAB programming for the convenience of engineering application.The result shows that,in the case of the lateral soil pressure in uniform or trapezoidal distribution,both the inner force and the radical convergence displacement of the lining ring have minor difference not more than 10%;and in the case of the lateral soil pressure in quadratic distribution,both the bending moment and shearing force of the lining ring have certain increment,while the axial force thereof have certain decrement.In addition,the“horizontal duck egg”deformation shows more severe for the quadratic distributed soil pressure.