Numerical simulation for large deformation problems of saturated soil poses an ongoing challenge since it requires the capabilities of modeling large deformations, interactions between solid skeleton and pore water, as well as fluidization behaviors. A hydro-mechanical coupled B-spline material point method is developed to simulate large deformations of saturated soils. Based on Biot's mixture theory, a single set of material particles is adopted to represent saturated soils where Darcy's law is employed to govern the motion of pore water and the momentum conservation of the mixture is used to govern the motion of solid skeleton. The convergence and effectiveness of the proposed method are examined by one-dimensional consolidation tests and quasi-static footing penetration into two-dimensional elastic saturated soils. The capability of simulating practical engineering for the proposed method is demonstrated by reproducing the dynamic process of three-dimensional saturated soil slopes with a strain-softening Drucker-Prager constitutive model. Results show that the coupled BSMPM well reveals the overall dynamic process of saturated soil slope involving evolution of shear bands, formation of graben and horst, and fluidization of progressive failures with improved computational accuracy and enhanced convergence, which demonstrates the proposed method is a promising approach for large deformation problems of saturated soils.

饱和土大变形问题的数值模拟是一个持续的挑战，因为它需要模拟大变形、固体骨架和孔隙水之间的相互作用以及流化行为的能力。A 水力机械耦合B-样条材料点法用于模拟饱和土的大变形。基于Biot混合理论，采用单组物质粒子来表示饱和土，采用达西定律控制孔隙水的运动，利用混合物的动量守恒来控制固体骨架的运动。通过一维固结试验和准静态基础渗透到二维弹性饱和土中，检验了所提出方法的收敛性和有效性。通过使用应变软化 Drucker-Prager 本构模型再现三维饱和土边坡的动态过程，证明了该方法模拟实际工程的能力。