Large deformation FEMLIP drained analysis of a vertical cut

Understanding and modelling the whole instability mechanisms of a slope are fundamental issues from a scientific and technical viewpoint. To date, small strain Lagrangian approaches have mostly been used in solid mechanics for modelling the failure stage, whereas Eulerian approaches are common in fluid mechanics for propagation analysis. A combination of both approaches allows the stability, failure and propagation stages of a slope to be analysed in a unique mathematical framework. To this end, this paper adopts a finite element method with Lagrangian integration points (FEMLIP), which is currently implemented in the ELLIPSIS code and has been used in geophysics and civil engineering applications. The method combines the robustness of an Eulerian mesh with the flexibility of a set of Lagrangian particles, which allows the history of the material to be taken into account. FEMLIP is first validated with reference to benchmarks with analytical solutions, and is then tested in a large deformation drained analysis of a vertical cut in coarse-grained soils. The results are compared with those provided by the standard engineering methods (1) the limit equilibrium method (LEM) and (2) standard stress-strain elasto-plastic FEM analysis. The comparison shows that FEMLIP is a reliable method for the analysis of both the stability and the instability of a vertical cut, and can be confidently used to analyse more complex problems related to natural slopes.