某地铁车站深基坑有限元模拟及现场监测分析

发布时间：2018-06-04 10:25

本文选题：地铁车站 + 深基坑　；参考：《长安大学》2017年硕士论文

【摘要】：城市轨道交通发展历史悠久,地铁车站深基坑工程是一项重要工程,社会关注度高,但基坑工程的理论和技术尚不完善,施工条件及周边环境往往又异常复杂,为了确保基坑施工过程的安全,有必要对依托地铁车站深基坑工程进行研究。本文以某地铁车站深基坑工程为背景,运用数值模拟的方法对基坑开挖全过程进行模拟,并将模拟结果与现场监测数据进行对比,论文主要研究内容及结论如下:(1)利用MIDAS/GTS有限元软件建立某地铁车站深基坑及相应土层的三维计算模型,模拟深基坑的开挖过程,重点分析了围护结构变形、坑底隆起以及地表沉降的变形规律,并对围护结构变形的影响因素进行分析,结果表明:随着基坑开挖深度的增加,围护结构水平向位移随深度的变化呈现出先增大后减小的趋势,基坑开挖至底时,围护结构水平位移达到最大,满足规范和设计的要求;在基坑开挖过程中,地表沉降变化曲线呈先增大后减小,最后逐渐趋于稳定的“抛物线”形式,基坑开挖至底时,地表沉降量达到最大,满足规范和设计要求;坑底隆起量变化的规律呈现出“中间大,两头小”的趋势,基坑开挖至底时,坑底隆起量在坑底中心位置附近达到最大值,满足规范和设计的要求;适当地增加内支撑刚度以及地下连续墙厚度能够有效抑制围护结构水平向位移。(2)对地铁车站深基坑进行现场监测,选取具有代表性的基坑监测点进行分析,主要从桩体深层水平向位移、支撑轴力以及基坑周围地表沉降三方面进行分析。监测数据满足规范与设计要求,表明该工程的围护结构设计方案合理有效。数值模拟结果与实测结果吻合度较高,说明所采用的计算模型是合理的,数值模拟结果可为类似基坑工程开挖前围护结构设计以及基坑监测方案的制定提供参考。
[Abstract]:The development of urban rail transit has a long history. The deep foundation pit engineering of subway station is an important project with high social concern. However, the theory and technology of foundation pit engineering are not perfect, and the construction conditions and surrounding environment are often extremely complex. In order to ensure the safety of foundation pit construction, it is necessary to study the deep foundation pit project relying on subway station. In this paper, based on the deep foundation pit engineering of a subway station, the whole excavation process of foundation pit is simulated by numerical simulation method, and the simulation results are compared with the field monitoring data. The main contents and conclusions of this paper are as follows: (1) using MIDAS/GTS finite element software, the three-dimensional calculation model of deep foundation pit and corresponding soil layer of a subway station is established, the excavation process of deep foundation pit is simulated, and the deformation of enclosure structure is analyzed emphatically. The deformation law of pit bottom uplift and surface settlement is analyzed. The results show that with the increase of excavation depth, the influence factors of deformation of retaining structure are analyzed. The horizontal displacement of the retaining structure increases first and then decreases with the depth. When the foundation pit is excavated to the bottom, the horizontal displacement of the retaining structure reaches the maximum, which meets the requirements of the code and design. The variation curve of surface subsidence increases first, then decreases, and finally tends to be a stable parabola. When the foundation pit is excavated to the bottom, the surface subsidence reaches the maximum, which meets the requirements of code and design. The rule of the quantity variation of pit bottom uplift shows the trend of "middle big, two ends small". When the foundation pit is excavated to the bottom, the quantity of bottom uplift reaches the maximum near the center of the pit bottom, which meets the requirements of specification and design. Properly increasing the stiffness of inner support and thickness of diaphragm wall can restrain the horizontal displacement of the retaining structure effectively.) the deep foundation pit of subway station can be monitored on the spot, and the representative monitoring points of foundation pit are selected for analysis. This paper mainly analyzes the deep horizontal displacement of the pile, the axial force of the support and the ground settlement around the foundation pit. The monitoring data meet the specifications and design requirements, which shows that the design scheme of the envelope structure of the project is reasonable and effective. The numerical simulation results are in good agreement with the measured results, which shows that the calculation model is reasonable. The numerical simulation results can provide a reference for the design of retaining structure before excavation of similar foundation pit and the establishment of foundation pit monitoring scheme.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU753

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