不对称荷载对深基坑围护变形的影响.pdfVIP

第 32 卷增刊 2 岩 土 力 学 Vol.32 Supp.2 2011 年 8 月 Rock and Soil Mechanics Aug. 2011 文章编号：1000－7598 2011 增刊 2 －0378 －06 不对称荷载对深基坑围护变形的影响 姚爱军，张新东 （北京工业大学岩土与地下工程研究所，北京 100124 ） 摘 要：以某城市轻轨换乘车站基坑为背景，通过现场监测的方法，分析深基坑两侧在不对称荷载作用下围护桩桩身水平位 移、桩顶水平位移和钢支撑轴力的变化以及基坑开挖对周边建（构）筑物的影响。找出深基坑围护变形规律，以对类似工程 设计施工提供经验指导。分析结果表明：不对称荷载对基坑围护桩桩身水平位移和桩顶水平位移产生的不对称变形作用非常 明显，在基坑一侧围护桩仍有较高安全系数的情况下，另一侧已经超限。基坑开挖导致两侧建（构）筑物产生不同的沉降。 由于围护桩产生不对称变形，钢支撑的支护效果有所减弱。 关 键 词：不对称荷载；基坑；监测分析 中图分类号：TU 473 文献标识码：A Influence of asymmetric load on supporting deformation for deep foundation pit YAO Ai-jun, ZHANG Xin-dong （Institute of Geotechnical and Underground Engineering, Beijing University of Technology, Beijing 100124, China ） Abstract: Based on the foundation pit of light rail transfer station in a city, through field monitoring, the variations of horizontal displacement of supporting pile, horizontal displacement of pile top, and axial force of steel brace are analyzed under asymmetric loads on two sides of deep foundation pit; and the influences of foundation pit excavation on surrounding buildings are also analyzed. Deformation law of supporting structure is obtained so as to provide experience and guidance for similar engineering design and construction. The results show that the effect of asymmetric load on asymmetric deformation caused by horizontal displacements of supporting pile and pile top is obvious. When one side supporting piles still have higher safety factors, the other side supporting piles exceed the limit value already. Excavation of foundation pit induces different settlements for the buildings on the two sides. Supporting effect of steel brace becomes weak due to the asymmetric deformation of supporting pile. Key words: asymmetric load; foundation pit; monitoring analysis 论不完善有很大关系。通过对所选择典型断面的监 1 引 言 测数据进行分析，发现在不对称荷载作用下基坑围 近年来全国城市轨道交通建设快速发展，地铁 护桩的稳定性存在较大差异，而且对两侧环境的影 建设越来越受到人们的重视，地铁车站基坑的安全 响也存在较大差异。该项目设计的围护桩一侧达到