In this paper, a computational framework based on the Smoothed Particle Finite Element Method is developed to study the coupled seepage-deformation process in unsaturated porous media. Governing equations are derived from the balance laws of solid and fluid phases considering partial saturation effects in porous media. Moreover, an hourglass control method is implemented to avoid the rank-deficiency issue in SPFEM and the moving least squares approximation technique (MLS) is implemented to eliminate the pore pressure oscillations when the low-order triangle element is used. The proposed coupled SPFEM formulation is validated through four elastic examples and one elasto-plastic example. Good agreement with the numerical or analytical results reported in the literature is obtained. Further, the rainfall-induced slope failure is studied, in which a suction-dependent elasto-plastic Mohr–Coulomb model is adopted to take account of the suction effect in unsaturated soil. The evolution of the suction and soil deformation during the rainfall period and the whole slope failure process are obtained. It is demonstrated that the proposed method is a promising tool in numerical investigations of both the triggering mechanisms and post-failure behavior of the rainfall-induced slope failure.

中文翻译：

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用两相全耦合平滑粒子有限元法模拟不饱和多孔介质的大变形破坏行为

本文开发了一种基于平滑粒子有限元法的计算框架来研究非饱和多孔介质中的耦合渗流变形过程。考虑到多孔介质中的部分饱和效应，控制方程是根据固相和液相的平衡定律推导出来的。此外，采用沙漏控制方法来避免SPFEM中的等级不足问题，并采用移动最小二乘近似技术（MLS）来消除使用低阶三角形单元时的孔隙压力振荡。所提出的耦合 SPFEM 公式通过四个弹性示例和一个弹塑性示例进行了验证。与文献中报道的数值或分析结果非常吻合。此外，还研究了降雨引起的边坡破坏，其中采用吸力相关的弹塑性莫尔-库仑模型来考虑非饱和土中的吸力效应。获得了降雨期间吸力和土体变形的演变以及整个边坡破坏过程。结果表明，该方法是对降雨引起的边坡破坏的触发机制和破坏后行为进行数值研究的有前景的工具。