地面堆载诱发下盾构管片变形分析

本文依托苏州地铁S1线某区间盾构隧道,针对后期沿线可能出现的堆载问题,采用地层-结构法建立精细化三维数值分析模型,系统地探究了堆载条件下,隧道上覆、穿越和下卧软土地层对盾构管片变形的影响规律。结果表明：在地面堆载作用下,上覆荷载经过土层扩散,使管片变形沿纵向呈“正态分布”,竖向变形最大处位于堆载位置正下方的拱顶处;隧道最大水平位移发生在荷载作用位置正下方管片的左右拱腰处,并且左右拱腰同时产生向外的水平位移;当堆载中心在隧道正上方时,隧道下卧软土层时隧道变形量最大,其次是隧道穿越软土层时,隧道上覆软土层时对隧道竖向变形影响最小;隧道下卧土层的弹性模量对隧道结构变形影响最大,且弹性模量越小,结构变形越明显。

Analysis of shield segment deformation induced by ground surcharge

This article relies on a shield tunnel in a certain section of the Suzhou Metro S1 line, and aims at the potential stacking problems along the line in the later period. The stratum-structure method is used to establish a refined three-dimensional numerical analysis model, and the influence of the tunnel overlying, crossing and underlying soft soil layer on the deformation of the shield segment under the condition of stacking is systematically explored. The result shows: Under the action of the ground load, the overburden load spreads through the soil layer, so that the deformation of the segment is "normally distributed" along the longitudinal direction, and the largest vertical deformation is located at the vault directly below the stacking position; The maximum horizontal displacement of the tunnel occurs at the left and right arches of the segment directly under the load, and the left and right arches simultaneously produce outward horizontal displacements; When the stacking center is directly above the tunnel, the tunnel deformation is the largest when the tunnel lies under the soft soil layer, and then when the tunnel passes through the soft soil layer, the vertical deformation of the tunnel is the smallest when the tunnel is overlaid with the soft soil layer; The elastic modulus of the underlying soil layer has the greatest influence on the deformation of the tunnel structure, and the smaller the elastic modulus, the more obvious the structural deformation.