Technical Note On the Assessment of Failure in Slope Stability Analysis by the Finite Element Method

摘要

From the above analysis, the following conclusions can be drawn 1) It is rational to use the proposed criterion of slope failure. The criterion says that when a slope arrives at the critical state, there exists a band such that all elements in the band would be in the plastic state and the band would go through the slope from the toe to the top. 2) The elasto-plastic matrix D_(ep) is positive definite for hardening materials, positive semidefinite for elastic-perfectly plastic materials and indefinite for softening materials. The last case is different from our conjecture. 3) The overestimation of plastic zones based on the finite element method with the elastic-perfectly plastic model is caused by the displacement interpolation pattern associated with isoparametric elements, which resists the formation of the shear band and makes a yielding element transfer the load exceeding its loading capability in isotropy instead of the fissure direction. 4) While plotting the contour lines of the effective strain epsilon-bar_p, a threshold of epsilon-bar_p slightly greater than zero can be selected to cut off those overestimated plastic zones.