柔性挡土结构空间土压力性状的三维有限元分析

为了研究基坑开挖对柔性挡土结构土压力空间分布规律的影响，进而为基坑的设计与安全防护提供相应依据，用ABAQUS建立基坑开挖的有限元模型，分析基坑开挖对挡土结构“单片墙”空间土压力的影响。考虑了不同刚度、有无支撑、不同开挖深度对挡土墙不同部位的土压力分布和挡土墙位移的影响，并将挡土结构三维土压力分布规律与二维数据进行了对比，验证了三维有限元模拟的必要性，对比了加支撑与否对基坑土压力空间分布的影响。结果表明:“单片墙”主动区土压力呈马鞍状分布，挡土结构后部土体的影响范围和下部土体的影响范围都约为2倍开挖深度；支撑结构极大地限制了墙后土体危险区域的范围，但是对墙下土体的限制作用并不是很明显。

Three-dimensional Finite Element Analysis on Earth Pressure Behavior of Flexible Retaining Structure

In order to investigate the influence of foundation pit excavation on the earth pressure spatial distribution law of flexible retaining structure, and to provide references for the design and safety protection of foundation pit,the finite element model of foundation pit excavation was established by ABAQUS and the influence of the foundation pit excavation on spatial earth pressure of retaining structure “monolithic wall”. The influences of different stiffness, with and without supports, different excavation depths on the earth pressure distribution and the displacement of different parts in retaining wall were considered. The three-dimensional earth pressure distribution of the retaining structure was compared with the two-dimensional data, and the necessity of three-dimensional finite element simulation was verified. The results show that “monolithic wall” active earth pressure zone appears a saddle shaped distribution, and the influence ranges of the behind and the bottom of retaining structure are about 2 times of excavation depth.Supporting structure greatly limits the scope of earth dangerous area behind the wall, but has no obvious limiting effect on the bottom of retaining structure.