Required strength of geosynthetics in a reinforced slope with tensile strength cut-off subjected to seepage effects

Abstract

The Mohr-Coulomb (M-C) yield criterion is found to overestimate the tensile strength of cohesive soils. By introducing the concept of tensile strength cut-off, the M-C criterion is modified to reduce or eliminate the tensile strength from the criterion. In this study, a new approach is proposed to investigate the stability of geosynthetic-reinforced slopes in cohesive soils subjected to seepage effects by means of the kinematic approach of limit analysis. The distribution of pore-water pressure is obtained using the numerical modeling software package, FLAC3D. A kinematically admissible failure mechanism is discretized to incorporate the results from the numerical simulation. The strength of geosynthetics required for maintaining the slope stability is evaluated from the work-energy balance equation. An optimization routine is used to seek out the maximum value among all possible results. Design charts providing the normalized required reinforcement under different parameters are plotted for a parametric study and convenient use in engineering. The obtained results show that less reinforcement is required in the presence of soil cohesion, and that the inclusion of the effect of tensile strength cut-off leads to a more conservative solution, which is more obvious in the presence of seepage effects.