填海区地铁盾构隧道下穿公路施工地层沉降规律的数值模拟

摘要

As indicated by the background information of Shenzhen Metro Line 2,the shield tunnel under passing Binhai Road in sea reclamation area,nonlinear finite element analysis software ABAQUS was used to set up a three-dimensional finite element model to analyze the laws for both the lateral and vertical settlements of ground surface,the horizontal displacement of stratum,and the layered settlement under the disturbance of tunnel construction.The results show that the ground settlement approximately shows normal distribution along tunnel transverse section.The width of ground settlement trough along tunnel vertical section is about 15.0 m.The closer the distance from tunnel excavation face,the greater is the disturbance from vehicle load and tunnel excavation to the horizontal displacement of stratum.In the action zone of vehicle load,both the ground settlement and horizontal displacement of stratum are greater than the non-action zone of vehicle load.Both the layered settlement of stratum and the width of settlement trough will decrease with the increase of the buried depth of stratum.The stratum settlement of upper part is generally greater than lower part.In the non-action zone of vehicle load,the settlement of soil mass above the central line of tunnel will increase with the increase of buried depth of stratum.%以深圳地铁2号线盾构隧道下穿填海区滨海大道公路为背景,利用非线性有限元分析软件ABAQUS建立三维有限元模型,研究在隧道施工扰动下,地表的横向沉降和纵向沉降、地层的水平位移和分层沉降的变形规律.仿真计算结果表明:在隧道横断面方向上地表沉降近似呈正态分布,在纵断面方向上地表沉降槽宽度约为15.0 m;距隧道开挖面越近,地层水平位移受车辆荷载和隧道开挖扰动越大；在车辆荷载作用区域,地表沉降和地层水平位移均大于非车辆荷载作用区域,地层的分层沉降和沉降槽宽度均随着地层埋深增加而减小,地层的上部沉降普遍大于下部；在非车辆荷载作用区域,隧道中心线上方的土体沉降随着地层埋深的增加而增加.