Hybrid Finite-Element Material-Point Method for Reinforced Slopes

Abstract

This paper proposes a modified Hybrid Finite-Element Material-Point Method (HFEMPM) for analyzing reinforced slopes. The method discretizes the soil using material points, and employs bar elements in the finite-element method to represent geosynthetics that can only withstand tensile loads. The interaction between geosynthetics and soil is naturally captured using the same background grid by HFEMPM. To capture their frictional contact more precisely, a specific procedure to evaluate the maximum frictional force of the bar exerted by the soil is proposed in this paper, which makes the modified HFEMPM more applicable in modelling reinforced soil. The μ(I) rheology from granular mechanics is introduced for stress updating of soil. The method is applied to simulate the experimental collapse of rod piles and centrifuge tests of reinforced slopes. Incorporating the μ(I) rheology for stress updating into the HFEMPM not only enables including the influence of particle size and initial soil strength on the stability of slopes, but also describing the effect of strain rate strengthening during the collapse process. Based on calculated results of stability with various reinforcement lengths and number of layers, a reference chart designed to summarize the optimal reinforcement scheme is provided as a guide in reinforced-soil engineering.