Anisotropic strength in discontinuity layout optimisation for undrained slope stability analysis

Journal article, 2025

Slope stability analysis in 2D ranges from the classical and conventional limit equilibrium method to the robust and com-putationally demanding finite element (FE) analysis. Discontinuity layout optimisation (DLO) is an interesting intermediate method that applies an upper bound limit analysis with the assumption of rigid-perfectly plastic soil behaviour. Here, the whole soil mass is discretized using a set of potential slip-lines and optimisation is used to identify the critical mechanism that can be formed from a subset of these lines that dissipates the least energy. This method has only been used for isotropic soil models, except for rare studies that included an anisotropic model. This paper introduces the use of an anisotropic failure criterion in DLO, based on the total stress-based NGI-ADP model. The performance of DLO with this simplified NGI-ADP model is compared with respect to failure mechanism and safety factor determined by corresponding FE analysis. The results show good agreement between the two methods and highlight the use of DLO as a powerful method with straightforward input parameters and low computational time for slope stability assessment.