某地铁车站深基坑支护方式的FLAC^(3D)模拟分析

Simulation and analysis on the support method for deep foundation pit of metro station by FLAC^(3D)

以南宁市大学鲁班路地铁车站基坑开挖支护为背景,对深基坑地下连续墙内支撑支护结构进行数值模拟分析。运用数值模拟软件FLAC^(3D)构建数值模型,分析基坑在不同开挖阶段下的位移、剪应变增量及内支撑轴力等。在地下连续墙内支撑支护下基坑底部最大竖向位移约为9.5 cm,基坑底部隆起位移量中间大,两边小;基坑侧壁最大水平位移为2.0 cm,出现在基坑长边中轴处;随着开挖深度的增大,剪应变增量影响范围呈现先略微减小再增大的趋势;内支撑轴力大小与基坑开挖深度成正比,且在第1道内支撑上出现了拉力。

As an example of excavation and supporting of university eastern subway station in Nanning, the combining diaphram wall with interior bracing support in deep pits is numerically simulated. A numerical simulation software named FLAC^（3D） is used to build a numerical model, in order to analyze contour map of displacement and shear strain increment about soil during different excavation steps. Under the support of inner bracing and diaphram wall, the maximum vertical displacement of foundation pit soil is about 9.5 cm and the uplift grows to the largest value in the central basement but it is smaller when the soil nears the foundation pit wall; the maximum horizontal displacement of foundation pit soil is about 2.0 cm and it appears on the central axis of the long side in the foundation pit; with the increase of excavation depth, scope of the shear strain increment slightly decreases firstly, and then increases significantly. Axial force of interior bracing is proportional to the excavation depth, and within the first interior bracing appeared on the tensile force.