考虑施工影响下地铁运营引起的地基土动特性及沉降研究

发布时间：2018-02-17 07:42

本文关键词： 地铁运行不同初始固结度三维有限元动三轴试验长期沉降　出处：《浙江大学》2013年硕士论文　论文类型：学位论文

【摘要】：地铁引起的长期沉降从时间上可以划分为两个阶段,即地铁运营前的沉降和地铁运营期间的沉降。其中地铁运营前的沉降主要由隧道掘进引起,它包含了由于土体损失、正面附加推力、摩擦力等原因产生的瞬时沉降以及由超孔隙水压力消散而产生的工后固结沉降。地铁运营期间的沉降主要由列车荷载作用下土体累积塑性变形和累积超静孔压消散引起,并受到隧道施工的影响。本文以杭州地区盾构隧道工程为研究背景,对考虑施工影响下列车运营引起的地基土动力特性及沉降进行了研究,研究内容及创新点包括： (1)将地铁列车移动荷载简化为多个移动轮轴荷载,分别以单个轮轴荷载和列车移动荷载为例,研究了地铁列车荷载作用线正下方地基土中的动应力特征、应力路径变化及主应力轴旋转,分析了不同隧道埋深下荷载作用线正下方土单元应力状态变化。 (2)在理论基础上,通过计算得到了盾构隧道施工完成时超孔隙水压力的分布,并利用MIDAS-GTS建立了三维有限元模型,得到了盾构施工完成后不同时间段内的地表沉降及超孔压分布规律。 (3)以杭州地铁一号线为背景,考虑杭州地铁车辆、车轮、轨道系统这三者之间的相互作用关系,建立了车厢、转向架、车轮三者运动耦合模型,将得到的荷载时程添加到三维有限元模型中分析得到了不同初始固结度下列车运行引起的地基土动力特性。 (4)研究在列车移动荷载作用下,地基土初始固结度分别为100%、90%、70%时,隧道拱顶、隧道起拱线和隧道拱底三个位置的超孔隙水压力变化规律。 (5)将工后长期沉降分为不排水累积塑性变形引起的沉降和累积超静孔压消散引起的沉降两部分,利用动三轴试验建立了杭州地区不同固结度下累积孔压模型,预测了杭州地铁不同初始固结度下列车运行引起的长期沉降。
[Abstract]:The long-term settlement caused by the subway can be divided into two stages in time, that is, the settlement before the subway operation and the settlement during the subway operation, in which the settlement before the subway operation is mainly caused by the tunneling, which includes the loss of soil mass. Frontal additional thrust, The instantaneous settlement caused by friction and the post-consolidation settlement caused by the dissipation of excess pore water pressure are mainly caused by the accumulated plastic deformation of soil under train load and the dissipation of accumulated excess pore pressure. And affected by the tunnel construction. Taking the shield tunnel engineering in Hangzhou area as the research background, the dynamic characteristics and settlement of foundation soil caused by train operation under the influence of construction are studied in this paper. The research contents and innovations include:. 1. The moving load of subway train is simplified into several moving axle loads. Taking the single axle load and the train moving load as examples, the dynamic stress characteristics in the ground soil directly below the train load line are studied. The stress path change and principal stress axis rotation are analyzed, and the stress state changes of soil element directly below the load line under different tunnel depth are analyzed. 2) on the basis of theory, the distribution of excess pore water pressure at the completion of shield tunnel construction is calculated, and the three-dimensional finite element model is established by using MIDAS-GTS. The distribution of surface subsidence and superpore pressure in different periods after shield construction is obtained. Taking Hangzhou Metro Line 1 as the background, considering the interaction among Hangzhou metro vehicle, wheel and track system, a kinematic coupling model of carriage, bogie and wheel is established. The dynamic characteristics of foundation soil caused by train operation under different initial consolidation degrees are analyzed by adding the load time program to the three-dimensional finite element model. (4) under the action of moving train load, the variation law of excess pore water pressure in the three positions of tunnel arch top, tunnel arch line and tunnel arch bottom is studied. The initial consolidation degree of foundation soil is 100 ~ 90 and 70 respectively. The long-term settlement after construction is divided into two parts: the settlement caused by undrained cumulative plastic deformation and the settlement caused by cumulative excess pore pressure dissipation. The cumulative pore pressure model under different consolidation degrees in Hangzhou area is established by dynamic triaxial test. The long-term settlement caused by train operation under different initial consolidation degrees of Hangzhou Metro is predicted.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU435;U231

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