MODELING OF A LINEAR SOIL-REINFORCEMENT MEMBER AND ITS IMPLEMENTATION INTO A RIGID-PLASTIC FINITE ELEMENT METHOD

Abstract

A rigid plastic finite element method is a numerical tool based on the limit theorem to solve directly the failure mode and its ultimate capacity, such as bearing capacity of shallow foundations. To model a soil-reinforcement effect by linear reinforcement members, the introduction of a constant length condition between two nodes can be found in the literature. In this article, the authors re-investigate this constant length condition and extend it for more general cases. Based on Lagrangian duality theory, a Lagrangian multiplier for this constant length condition can be interpreted as a constraint force between the two nodes. The authors introduce an additional inequality constraint on this Lagrangian multiplier in a hybrid formulation of a rigid plastic finite element method to express finite and anisotropic strength properties of linear reinforcement members. Some numerical examples are presented to demonstrate the ability of the proposed method.