摘要
为了研究基坑深度对支撑式基坑支护结构的影响情况,建立灌注桩加一道混凝土内支撑和灌注桩加两道混凝土内支撑基坑支护模型,对不同挖深时挡土结构、支撑结构、整体稳定安全系数和基坑周边环境等受力或变形规律进行分析.研究结果表明,挡土结构最大受力与变形、最下层支撑最大轴力和坑边最大地面沉降均随基坑深度的增加而增加,且均在开挖至坑底工况时达到最大;桩身最大位移与基坑深度近似成正比;基坑整体稳定安全系数随基坑深度的增大近似线性减小;支撑轴力、坑边地面沉降量同坑边荷载成正比,基坑整体稳定安全系数与坑边荷载成反比;在两道支撑支护的基坑中,首层支撑不受基坑深度的影响.
Abstract
In order to study the influence of over-excavation on the supporting structure of supported foundation pits,we establish the models of foundation pits with one concrete internal support and two concrete internal supports,and analyze the force or deformation patterns of the retaining structure,supporting structure,overall stability safety coefficient,and the surrounding environment of the foundation pits at different depths of over-excavation.The results show that the maximum values of force and deformation of the retaining structure and ground settlement at the edge of the pit occur in the excavation to the bottom of the pit;in the pit supported by two supports,the first layer of support is not affected by the over-excavation of the pit;the maximum force and deformation of the retaining structure,the maximum axial force of the support,and the maximum ground settlement at the edge of the pit increase with the increase of the depth of over-excavation of the pit,and the maximum displacement of the pile body is proportional to the depth of over-excavation;the overall stability safety coefficient of the pit increases with the depth of over-excavation.The overall stability and safety coefficient of the foundation pit decreases linearly with the increase of the over-excavation depth of the foundation pit,but it always meets the requirement of the code for the overall stability and safety coefficient of the first-level foundation pit;the axial force of the support,the ground settlement at the edge of the pit are proportional to the load at the edge of the pit,and the overall stability and safety coefficient of the foundation pit is inversely proportional to the load at the edge of the pit.
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万方数据