Limit design of earth reinforcement methods considering displacement field

This paper proposes a limit design technique for slope and retaining wall reinforced by geotextile, which is tentatively called LSFEA (Limit State Finite Element Analysis). LSFEA, which is fundamentally based on the initial stress method for nonlinear stress-strain analysis in FEM, aims to fill a large gap existing between FEM and LEM (Limit Equilibrium Method) which is a traditional design technique also in earth reinforcement problems. LSFEA employs Mohr-Coulomb and Coulomb yield criteria respectively for soil mass and friction interface. By assuming a linear elastic response before yielding and a non-associated flow rule after yielding as a stress-strain relationship, LSFEA provides a definite collapse mode similar to a potential slip surface assumed in LEM. It is difficult for LEM to consider the kinematical condition at failure and the stiffness of material. LSFEA enables to compensate for most of these defects in LEM, because LSFEA is based on FEM. LSFEA can be effectively applied to stability problems in which the kinematical condition and material stiffness largely affect the solution.