An improved discretization-based kinematic approach for stability analyses of nonuniform c-φ soil slopes

This paper proposes an improved discretization-based kinematic approach (DKA) with an efficient and robust algorithm to investigate slope stability in nonuniform soils. In an effort to ensure rigorous upper-bound solutions which may be not satisfied by the initial DKA based on a forward difference method (DKA-FD), a central and backward difference “point-to-point” method (DKA-CD and DKA-BD) is proposed to generate discretized points to form a velocity discontinuity surface. Varying (including constant) soil frictional angles along depth are discussed, which can be readily considered in the improved DKA-CD. Work rate calculations are performed to derive upper-bound formulations of slope stability number, and critical failure surface is correspondingly obtained at limit state. The comparison with forward and backward difference methods clearly reveals that the improved DKA-CD could significantly reduce the mesh-dependency issue and enhance efficacy of slope stability analyses in nonuniform soils.