On the assessment of failure in slope stability analysis by the finite element method

A study was conducted for qualitative analysis of the finite element slope stability failure based on the elastic-perfectly plastic model. The study found that when a slope arrives at the critical state, there exists a band in which all elements will be in the plastic state and the band will go through the slope from the toe to the top. The study observed that the elasto-plastic matrix is positive definite for hardening materials, positive semidefinite for elastic-perfectly plastic materials, and indefinite for softening materials. The study also observed that the displacement interpolation pattern associated with isoparametric elements can resist the formation of the shear band and produce an element to transfer the excess load in isotropy instead of the fissure direction.