An Upper Bound Formulation for Stability Assessment of Variably Saturated Reinforced Soils

Abstract

A novel unified numerical limit analysis method is proposed to study variably saturated soils reinforced by flexible inclusions. An effective stress-based criterion is utilized to determine the shearing resistance of variably saturated soil-reinforcement interfaces, which is verified through available experimental results. Soils are then treated as single-phased materials and equivalent forces are respectively established within the soil mass and along the interface. In this way, the role of matric suction profiles in stabilizing the reinforced soils under different hydraulic conditions can be analyzed in a more efficient way. To represent the limited tensile strength and negligible compressive strength of the flexible reinforcement, a strategy is proposed to calculate its plastic dissipation rate without the incorporation of stress variables. Plastic dissipation rates of the soil, the reinforcement, and their interfaces are computed using only kinematic variables. The solution domains of the soil, the reinforcement, and the interface are discretized using linear and constant strain finite elements, respectively. Finally, numerical examples are provided to discuss the effect of matric suction on the stability of reinforced structures made of marginal soils.