Stability analysis with FEM: strain softening vs. strength reduction approach

In slope stability analysis, a progressive failure can occur due to a reduction of strength with increasing strain. This paper examines slope stability analysis with strain softening behaviour and their comparison with the strength reduction approach applying the finite element method. The results show that failure mechanisms obtained by both approaches are almost identical. The ratio between peak and reduced strength in strain softening behaviour is correlated with the factor of safety (FOS) in strength reduction technique. For strain softening materials, it cannot be assumed that a safety factor (FOS) greater than one based on peak shear strength means stability, because deformations may lead to a local loss of strength, requiring mobilization of additional strength at other points along the slip surface. This mechanism leads to additional movement and further strain softening. Therefore, if the peak strength is mobilized anywhere along the failure surface, a slope in strain softening materials is at risk of progressive failure. Analysis of slope stability was done by the finite element method using the Mohr Coulomb failure criterion and an advanced Multilaminate model. In the proposed paper, the Multilaminate model for soil, enhanced with a non-local formulation as regularisation method, and a simple Mohr Coulomb model in invariant formulation are compared.

Dibuat oleh : Indra Noer Hamdhan,  Helmut F. Schweiger

E-mail: indranh@itenas.ac.id, helmut.schweiger@tugraz.at

Kata Kunci :

Keterangan :  Makalah ini  dimuat pada Proceedings The 60th Geomechanics – Colloquy 2011, ÖGG Workshop 2011, Computational Methods in Geomechanics – Failure Mechanism and Parameter, Identification, Salzburg Austria 12 Oktober 2011

Stability analysis with FEM: strain softening vs. strength reduction approach