基于PLAXIS的复合土钉支护变形及内力分析

为了研究复合土钉支护基坑变形规律以及结构内力变化,以长沙高新区公安分局办公楼深基坑工程为基础,运用PLAXIS有限元程序对基坑开挖支护过程进行数值模拟分析,并与实测数据相对比,结果表明:1PLAXIS有限元程序能有效模拟基坑开挖支护过程,可用于对实际工程的基坑变形和结构内力变化的预测;2坑壁位移的曲线分布大致呈"鼓肚子"状,基坑周围地表最大沉降发生在距坑壁一定距离处,而不是坑壁附近。基坑底的隆起量在坑壁处最小,在基坑中心处最大;3锚杆锚固段轴力随开挖深度的增大而增大,沿长度方向减小,土钉轴力分布呈现"中间大,两头小"的特征。

Analysis on Deformation and Internal Force of Composite Soil Nailing Support Based on PLAXIS

In order to learn what excavation deformation law the composite soil nailing support have and how its internal force change, this paper, depending on the deep excavation engineering for the office building of Changsha High-tech Zone Public Security Sub-bureau, made numerical simulation on the excavation and supporting process with PLAXIS finite element program, and compared with the measured data. The result shows that, ① PLAXIS finite element programe may simulate the excavation and supporting process, and is available for actual engineering prediction; deformation of foundation pit and structural internal force;② the pit wall displacement curve presents “drum belly” approximately, and the maximum settlement of the ground surface around the foundation pit arises at the place where is not close to the pit wall, but with certain distance; the bottom heave is minimum near the pit wall and maximum at the pit cente; ③ the anchor bolt has the axial force in the anchoring section increase with the excavation depth, and decrease lengthwise; the distribution of the soil nailing axial force is characterized as “big in middle, small at two head”.