某基坑围护结构变形监测与数值模拟分析

Deformation Monitoring and Numerical Analysis of a Deep Excavation Supporting Structure

结合苏州市某基坑工程,分别对基坑施工过程中采用不同围护结构的桩(坡)顶部水平和竖向位移、地下水位及坑外地表的监测结果分别进行了整理,并对监测数据进行了分析。结果表明,随基坑开挖,不同围护结构的桩(坡)顶水平位移逐渐向坑内侧偏移;桩(坡)顶竖向位移累计绝对值均逐渐增加,各测点的桩(坡)顶竖向位移时程曲线的变化趋势基本一致;坑周土体虽出现沉降,但坑外地表沉降累计值不大且在报警值之内。表明采用SMW工法桩、钻孔灌注桩结合三轴搅拌桩及两级放坡结合搅拌桩的支护形式是有效的。结合ABAQUS有限元软件对基坑支护结构进行了数值模拟分析,结果表明数值模拟与监测结果的变化规律较为一致,表明基坑支护结构设计合理。

Combined with a deep excavation project in Suzhou,the monitoring results of the horizontal and vertical displacement at the top of pile(slope),groundwater level and surface outside the excavated area with different supporting structures in the process of the deep excavation construction are collected and the monitoring data are systematically analyzed.The results show that with the excavation progress,the horizontal displacement of pile(slope)top of different retaining structures gradually shifts to the inside of excavated area.The cumulative absolute value of the vertical displacement of pile(slope)top increases gradually,and the change trend of time history curve of the vertical displacement of pile(slope)top at each measuring point is essentially the same.The soil around the excavated area has settlement,but the cumulative value of the surface settlement outside the pit is not large and is within the allowable value.Therefore,the support form of the SMW method pile,bored pile combined with triaxial mixing pile and two-stage slope combined with mixing pile is effective.Finally,the numerical analysis of the deep excavation supporting structure is performed by using the ABAQUS finite element software.The results show that the variation relationship of the numerical simulation and monitoring results is consistent,indicating that the design of the deep excavation supporting structure is reasonable.