深基坑挡土桩土拱效应特征分析

土拱效应是挡土桩工作原理的基础。采用有限元法首先研究了一个真正土拱的受力特征，以此为基础，分析了深基坑挡土桩后土体的受力状态；指出挡土桩后的土体可以分为3个区域：拱底应力区、土拱区和拱顶均匀应力区。在拱底应力区，最大主应力为拉应力；在土拱应力区，其受力特征与真正的土拱相同。给出了这3个区域的分界线特征，并讨论了荷载及挡土桩净距等因素对土拱区形状的影响。

Feature Analysis on Soft Arching Effect of Retaining Piles for Deep Foundation Pit

Soil arching effect is the basis for retaining piles.In this paper,FEM is first used in the study of stress and deformation for a real soil arch,and then based on it,stress and deformation condition behind retaining piles for deep pit is analyzed.The soil behind retaining piles can be divided into 3 region:(1) the region under soil arch,(2) soil arching region,(3) uniform stress zone in crown arch.In region(1),the maximum principal stress is tensile stress;the stress state in region(2) is the same with that of the real soil arch.The boundary of these 3 regions is studied.The influence on the structure of soil arching region by loading and clear space of retaining piles is also discussed.