基于FEM-SPH耦合方法的挡土墙墙后土体变形破损研究

Damage Analysis of Soil behind Retaining Wall Based on FEM-SPH Coupling Method

挡土墙发生较大位移时,墙后土体往往出现裂缝,应用传统有限元法(FEM)计算墙后土体受力变形时存在困难。FEM-SPH的耦合方法结合了FEM的高精度、高效率和SPH粒子处理大变形的能力,可以较好地模拟裂缝的衍生与发展演化。本文介绍了SPH方法的基本原理与FEM-SPH的耦合方法,使用FEM-SPH自适应耦合算法对平动位移模式下挡土墙墙后土体的裂缝衍生与墙后土压力进行了三维数值计算,并与试验结果进行了对比,结果表明:(1)FEM-SPH方法可以较好地模拟挡土墙墙后土体的裂缝衍生;(2)墙后滑坡推力峰值在距离墙顶2/3处;(3)挡土墙平动模式下,张拉裂缝与剪切裂缝交替出现,张拉裂缝的出现由远挡墙向近挡墙的顺序衍生,剪切裂缝的出现由土体下端向上端的顺序衍生。研究结果可以为解决岩土体大变形问题提供新的思路。

When a retaining wall experiences significant displacement,cracks often develop in the backfill soil,posing challenges for traditional finite element method(FEM)simulations of the soil's stress and deformation.The coupling of FEM with smoothed particle hydrodynamics(SPH),known as FEM-SPH,combines the high precision and efficiency of FEM with the ability of SPH particles to handle large deformations,enabling effective modeling of crack initiation,propagation,and evolution.This paper presented the fundamental principles of the SPH method and the coupling approach of FEM-SPH.A three-dimensional numerical computation was conducted using the FEM-SPH adaptive coupling algorithm to simulate crack development in the backfill soil and the associated wall pressure in a translational displacement mode of a retaining wall.The numerical results were compared with experimental data,with the following conclusions:(1)The FEM-SPH method can effectively simulate crack initiation and propagation in the backfill soil of a retaining wall.(2)The peak thrust of backfill landslide occurred at approximately 2/3 of the distance from the top of the wall.(3)Under the translational displacement mode of the retaining wall,tensile cracks and shear cracks occurred alternately,with tensile cracks propagating sequentially from the far wall to the near wall,while shear cracks propagated from the bottom to the top of the soil mass.These findings provide new insights for addressing significant deformations in geotechnical engineering of soil structures.