徐州地铁车站深基坑变形规律研究

发布时间：2018-05-10 13:31

本文选题：深基坑 + 空间效应　；参考：《辽宁工程技术大学》2014年硕士论文

【摘要】：地铁车站深基坑围护结构设计及其变形规律的研究是地铁车站建设过程中最重要的环节之一,因此,对地铁车站深基坑在开挖过程中变形规律的研究具有重要的工程应用价值。本文运用三维有限差分软件FLAC3D,考虑基坑开挖过程中存在时空效应,对徐州地铁车站深基坑开挖过程进行模拟,分析每层土体开挖后基坑底部土体回弹、基坑周围土体沉降、内支撑轴力、围护结构侧移的变化规律,并将模拟结果与现场监测结果相对比,得出：基坑底部土体回弹沿基坑宽度方向呈对称分布,随开挖深度增加,回弹形式由均匀回弹变成中间大两边小；基坑周围地表沉降曲线形状呈抛物线型,且最大地表沉降值发生在距离基坑边缘约1倍开挖深度位置处,随着基坑开挖深度的增加,沉降值逐渐增大,最大沉降点有向外移动现象；斜撑轴力随着斜撑长度增加而增大,且斜撑轴力明显小于直撑轴力,直撑轴力的最大值出现在基坑中部范围内；基坑挡土墙侧移总体变化趋势是两头小中间大,随着基坑开挖深度的增加侧移量也增加,在第2、3道支撑设置后,挡土墙的水平侧移量继续增加,但增加幅值明显减小；随着开挖层厚度的增加,基坑周围土体沉降和围护结构变形也随之增加,但随着开挖段宽度的增加,周围土体沉降减少而围护结构侧移量增大,二者成此消彼长的关系。
[Abstract]:The design of the retaining structure and the deformation law of the deep foundation pit of the subway station is one of the most important links in the construction of the subway station. Therefore, the study on the deformation law of the deep foundation pit of the subway station during the excavation process has important engineering application value. In this paper, the three-dimensional finite-difference software FLAC3D is used to simulate the excavation process of the deep foundation pit of Xuzhou Metro Station, considering the space-time effect in the excavation process of the foundation pit, and to analyze the springback of the soil at the bottom of the foundation pit after each layer of soil is excavated, and the settlement of the soil around the foundation pit. By comparing the simulation results with the field monitoring results, it is concluded that the springback of the soil in the bottom of the foundation pit is symmetrically distributed along the width of the foundation pit and increases with the depth of excavation. The shape of the surface settlement curve around the foundation pit is parabola, and the maximum surface settlement occurs at the position of about 1 times the excavation depth from the edge of the foundation pit, and with the increase of the excavation depth of the foundation pit, the springback form is changed from uniform springback to the middle big and small, and the shape of the surface settlement curve around the foundation pit is parabola. The settlement value increases gradually, the maximum settlement point moves outward, the axial force of inclined brace increases with the increase of inclined brace length, and the axial force of oblique brace is obviously smaller than that of straight brace, and the maximum axial force of straight brace appears in the middle of foundation pit. The overall trend of lateral displacement of retaining wall of foundation pit is large in the middle of two ends, and the amount of lateral displacement also increases with the increase of excavation depth. The horizontal lateral displacement of retaining wall continues to increase, but the amplitude of increase decreases obviously after the installation of the second third support. With the increase of the thickness of the excavation layer, the settlement of the soil and the deformation of the surrounding structure also increase, but with the increase of the width of the excavation section, the settlement of the surrounding soil decreases and the lateral displacement of the surrounding structure increases.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753

【参考文献】