软弱夹层对深基坑水平位移影响的数值模拟分析

以某深基坑支护工程为背景，研究了软弱夹层对基坑水平位移的影响。利用有限元分析软件PLAXIS 2D和M C土体本构模型对该工程排桩预应力锚杆支护段进行数值模拟。对比分析了软弱夹层的黏聚力、内摩擦角、厚度、埋置深度对基坑水平位移的影响，得到了这些因素对基坑水平位移的影响规律。结果表明:软弱夹层的存在对基坑水平位移有较大影响；内摩擦角对基坑水平位移的影响比黏聚力更加明显；黏聚力和内摩擦角同时变化引起基坑水平位移的变化大于单一参数变化引起的基坑水平位移变化之和；基坑水平位移随软弱夹层厚度的增大而增大；随着埋置深度的增大，基坑水平位移呈现先增大后减小的趋势。

Numerical Simulation Analysis of Influence of Soft Interlayer on Horizontal Displacement of Deep Foundation Pit

Based on a deep foundation pit supporting project, the influence of soft interlayer on the horizontal displacement of foundation pit was studied. The finite element analysis software PLAXIS 2D and Mohr-Coulomb soil constitute model were used to simulate the pile-prestressed anchor support section of the project. The influences of the cohesion, internal friction angle, thickness and embedded depth on the horizontal displacements of the foundation pit were compared and analyzed, and the effect laws of these factors on the horizontal displacement of foundation pit were obtained. The results show that the existence of soft interlayer has great influence on the horizontal displacement of foundation pit; influence of internal friction angle on the horizontal displacement of foundation pit is more obvious than that of cohesion; changes of horizontal displacement of foundation pit caused by cohesion and internal friction angle changing at same time are more than the sum of changes of the single parameter; horizontal displacement of foundation pit increases with thickness of the soft interlayer increasing; the horizontal displacement of foundation pit increases first and then decreases with the increase of embedded depth.