饱和地基地铁盾构隧道车致动应力响应特征  

Response of Dynamic Stress in Saturated Soil Induced by Moving Metro Train in Shield Tunnel

作　　者：狄宏规[1] 周顺华[1] 何超[1] 肖军华[1] 罗喆[1] DI Honggui;ZHOU Shunhua;HE Chao;XIAO Junhua;LUO Zhe(Key Laboratory of Road and Traffic Engineering of Ministry of Education,Tongji University,Shanghai 201804,China)

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804

出　　处：《铁道学报》2018年第8期160-167,共8页Journal of the China Railway Society

基　　金：国家自然科学基金(51478353;51008158)

摘　　要：将盾构隧道衬砌和壁后注浆层视为Flügge双层圆柱壳、将饱和土体视为包裹在隧道外的中空圆土柱、将列车荷载视为一系列以恒速移动的轮载,基于分离变量法求解圆柱壳运动方程,并借助Helmholtz矢量分解定理求解Biot波动方程,结合边界条件,建立车辆-隧道-土体系统动力响应半解析模型。基于该模型,探讨饱和黏性土地基车致动应力的时空分布特征。结果表明:隧道注浆层底部土体正应力τ_(yy)幅值最大,τ_(xx)和τ_(zz)幅值接近,约为0.5τ_(yy);土体正应力及孔压幅值随着深度的增加而减小,正应力中τ_(xx)沿深度衰减最快,τ_(yy)衰减最慢;剪应力τyz幅值随着深度的增加先增大后减小,至注浆层底部以下9 m处,地基动应力衰减为最大值的20%及以下。To investigate the dynamic stress in saturated soil induced by the movement of metro train in a shield tunnel, the lining and grouting layer of a shield tunnel were conceptualised as a double cylindrical shell and the saturated soil was conceptualised as a hollow cylinder with infinite radial extent, respectively. The metro train load was simplified as a series of wheel loads moving at a constant speed. The motion equations of the Flugge＇s shell were solved by the sepa ration of-variables method and the Helmholtz decomposition theorem was used to solve the Blot＇s wave equations. Based on the boundary conditions, a semi analytical model for the dynamic response of train tunnel soil system was es tablished, where the spactime distribution characteristics of the train induced dynamic stresses in saturated soil were analyzed. The results show that the magnitude of the soil normal stress τyy at the bottom of tunnel grouting layer is greater than that of τxx and τxx, and the magnitudes of τxx and τxx are close to 0.5ryy. The amplitude of the normal stress and porewater pressure of the soil is decreasing with the increase of the depth. Among three normal stresses, τxx has the largest attenuation ratio along the depth while ryy has the smallest attenuation ratio. The amplitude of shear stress τyy increases first and then decreases with the increase of the depth. At 9 m below the bottom of the grouting layer, the magnitudes of dynamic stresses attenuate to 20 % of the maximum value and below.

关 键 词：盾构隧道 饱和土 PiP模型 注浆层 

分 类 号：U451.3[建筑科学—桥梁与隧道工程]