列车荷载作用下黄土地区隧道振动响应分析与运营沉降研究
发布时间：2018-11-11 21:42
【摘要】：随着地下轨道交通的快速发展,地铁列车荷载引发的土体振动和变形成为影响地铁运营安全的重要因素。目前关于动荷载作用下黄土动力特性和变形研究多基于地震或震陷。与地震荷载相比,地铁列车荷载具有小幅值、长持续时间等特点,而对于地铁列车荷载长期作用下黄土的动力特性和变形研究相对较少。基于以上原因,本文以西安地铁四号线为工程背景进行了以下研究:1)通过振动三轴试验,研究非饱和黄土的动应力—动应变和动应力—残余应变关系,得到:在同一动应变之下围压、固结应力比越高,动应力幅值越大。2)通过循环三轴试验,得到随着动应力幅值的增加,非饱和黄土残余应变也随之增加。3)ABAQUS数值分析结果表明:竖直方向振动响应大于水平方向振动响应;地层的振动响应大于地表振动响应;地表振动响应在距隧道轴线一定水平距离会出现“局部放大”现象;地层振动响应在地表附近和隧道邻近区域出现了“局部放大”现象;荷载频率越低,地表的振动响应越大;在隧道邻近区域之外的土体,频率越低振动响应越大;隧道邻近区域的土体,振动响应规律各不相同,高频荷载的加速响应较大,低频荷载的速度响应较大,中间频率荷载的位移响应较大;速度为某一特定值时,振动响应最大。4)使用Chai-Miura模型结合分层总和法研究了塑性沉降的累积效应,得出:隧道邻近区域土体的静动偏应力分布会发生突变;在地铁行车荷载作用初期,地表沉降增长很快,增长速度随着地铁行车荷载循环作用次数的增加而逐渐变缓,沉降稳定时,地面的沉降最大值为18.0mm,隧道下方的沉降为1.07mm;塑性变形主要发生在隧道邻近区域之中。
[Abstract]:With the rapid development of underground rail transit, the vibration and deformation of soil caused by train load have become an important factor affecting the safety of subway operation. At present, the dynamic characteristics and deformation of loess under dynamic load are mostly based on earthquake or earthquake subsidence. Compared with the seismic load, the subway train load has the characteristics of small value, long duration and so on. However, the dynamic characteristics and deformation of loess under the long term load of subway train are less studied. Based on the above reasons, this paper takes Xi'an Metro Line 4 as the engineering background to carry out the following research: 1) through the vibration triaxial test, the dynamic stress-dynamic strain and the dynamic stress-residual strain relationship of unsaturated loess are studied. It is obtained that the higher the consolidation stress ratio, the larger the amplitude of dynamic stress under the same dynamic strain. 2) through cyclic triaxial test, it is obtained that the amplitude of dynamic stress increases with the increase of dynamic stress amplitude. The residual strain of unsaturated loess also increases with it. 3) the results of ABAQUS numerical analysis show that the vertical vibration response is larger than the horizontal vibration response; The ground vibration response is larger than the surface vibration response, the ground vibration response will appear the "local amplification" phenomenon at a certain horizontal distance from the tunnel axis, the formation vibration response will appear the "local amplification" phenomenon near the ground surface and the tunnel adjacent area. The lower the load frequency, the greater the vibration response of the surface, and the larger the vibration response of soil outside the adjacent region of tunnel. In the adjacent region of tunnel, the vibration response of soil is different, the acceleration response of high frequency load is larger, the velocity response of low frequency load is larger, and the displacement response of intermediate frequency load is larger. When the velocity is a certain value, the vibration response is maximum. 4) the cumulative effect of plastic settlement is studied by using Chai-Miura model and stratified summation method. At the initial stage of the train load, the surface subsidence increases rapidly, and the growth rate is gradually slowed down with the increase of the number of times of the subway train load cycle. When the settlement is stable, the maximum settlement of the ground is 18.0mm. The settlement under the tunnel is 1.07mm; Plastic deformation mainly occurs in the adjacent region of the tunnel.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451
[Abstract]:With the rapid development of underground rail transit, the vibration and deformation of soil caused by train load have become an important factor affecting the safety of subway operation. At present, the dynamic characteristics and deformation of loess under dynamic load are mostly based on earthquake or earthquake subsidence. Compared with the seismic load, the subway train load has the characteristics of small value, long duration and so on. However, the dynamic characteristics and deformation of loess under the long term load of subway train are less studied. Based on the above reasons, this paper takes Xi'an Metro Line 4 as the engineering background to carry out the following research: 1) through the vibration triaxial test, the dynamic stress-dynamic strain and the dynamic stress-residual strain relationship of unsaturated loess are studied. It is obtained that the higher the consolidation stress ratio, the larger the amplitude of dynamic stress under the same dynamic strain. 2) through cyclic triaxial test, it is obtained that the amplitude of dynamic stress increases with the increase of dynamic stress amplitude. The residual strain of unsaturated loess also increases with it. 3) the results of ABAQUS numerical analysis show that the vertical vibration response is larger than the horizontal vibration response; The ground vibration response is larger than the surface vibration response, the ground vibration response will appear the "local amplification" phenomenon at a certain horizontal distance from the tunnel axis, the formation vibration response will appear the "local amplification" phenomenon near the ground surface and the tunnel adjacent area. The lower the load frequency, the greater the vibration response of the surface, and the larger the vibration response of soil outside the adjacent region of tunnel. In the adjacent region of tunnel, the vibration response of soil is different, the acceleration response of high frequency load is larger, the velocity response of low frequency load is larger, and the displacement response of intermediate frequency load is larger. When the velocity is a certain value, the vibration response is maximum. 4) the cumulative effect of plastic settlement is studied by using Chai-Miura model and stratified summation method. At the initial stage of the train load, the surface subsidence increases rapidly, and the growth rate is gradually slowed down with the increase of the number of times of the subway train load cycle. When the settlement is stable, the maximum settlement of the ground is 18.0mm. The settlement under the tunnel is 1.07mm; Plastic deformation mainly occurs in the adjacent region of the tunnel.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451
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