过街隧道施工对地下管线影响的三维数值模拟

3D NUMERICAL SIMULATION OF EFFECT OF UNDERGROUND URBAN STREET-PASSAGE TUNNEL CONSTRUCTION ON ADJACENT PIPELINE

采用三维有限元方法分析过街隧道施工引起的相邻地下管线变形和受力,研究路面、管线材质、管线埋深、管线与隧道轴线间距以及管线与土体弹性模量比等因素对地下管线位移的影响,并与实测值进行比较。研究结果表明:有限元模拟结果与实测值较吻合,略大于实测值;路面的存在使浅埋管线的位移变小、沉降槽宽度变窄;隧道开挖引起的管线水平位移远小于竖向位移;与隧道垂直管线的竖向位移和水平位移最大值与管线埋深基本呈线性变化,且随着管线与土体模量比的增大逐渐减小;与隧道平行管线的最大竖向位移和水平位移值均随管线间距和埋深之比(L/h)增大而减小,最大水平位移值与L/h值基本呈线性关系,最大竖向位移值在L/h<10时迅速增大;管线最大拉应力和压应力均随着L/h值增大而减小,当L/h<5时急剧增大,当L/h≥5时缓慢减小,且应力值比较小。

Three-dimensional finite element analysis model is established to simulate the effects of tunnel excavation on adjacent underground pipeline. The influences of pavement, pipeline material, buried depth, spacing distance between pipeline and tunnel, and elastic modulus ratio of soil and pipeline on the displacement of underground pipeline is discussed. Then the calculation values are compared with the test values. It shows that the results of finite element numerical simulation are well in accordance with but slightly larger than measured data. Displacement of shallow-buried pipeline decreases and settlement trough width becomes narrow due to the existence of pavement. Horizontal displacement of underground pipeline induced by tunnel excavation is far less than vertical displacement. The maximum horizontal displacement and vertical displacement of pipeline perpendicularly crossing with tunnel change linearly with buried depth of pipelines, and decrease with the increase of elastic modulus ratio of soil and pipeline. Defining L as ratio of distance between axial lines of pipeline and tunnel, and h as buried depth of pipelines, The maximum horizontal displacement and vertical displacement of pipeline parallel with tunnel decrease with the increase of L/h. The maximum horizontal displacement changes linearly with L/h, and the maximum vertical displacement increases quickly when L/h〈 10. The maximum stress of pipeline decreases with the increase of L/h, and increases quickly when L/h 〈： 5. The maximum stress of pipeline changes slowly with small value when L/h 〉1 5.