Elastic-plastic cell-based smoothed finite element method solving geotechnical problems

Abstract: An elastic-plastic cell-based smoothed finite element method (CSFEM) is proposed for geotechnical analysis of soils and rocks exhibiting nonlinear and path-dependent behaviors. By introducing strain smoothing over subcell domains and employing a consistent stress return-mapping algorithm, the method enhances stress accuracy, alleviates volumetric locking, and reduces sensitivity to mesh distortion while retaining the flexibility of polygonal elements. The formulation is implemented in ABAQUS via a user-defined element and validated through benchmark and practical problems, including a pressurized thick cylinder, biaxial soil test, strip footing bearing capacity, tunnel excavation, and slope stability. Numerical results show excellent agreement with analytical solutions and conventional FEM, with smoother stress fields, improved convergence, and higher accuracy in ultimate load prediction. These findings demonstrate that CSFEM provides a stable and efficient framework for elastic-plastic analysis of complex geotechnical problems.