Numerical investigation on the response of ground-reinforced embankments under repeated impact

Abstract

Ground-reinforced embankment (GRE) is an effective and environmentally friendly technique of rockfall intervention. These earth structures are built with layers of compacted soil alternated with geotextiles, geogrills, metallic wire stripes or nets. GREs are designed to sustain repeated rock impact during their service life, but there is very little experimental or numerical research on the GRE response under such impact conditions. A comprehensive numerical investigation of GRE response under repeated rock impact is carried out. The GRE is built with several layers of sand wrapped by geosynthetics. An advanced elastoplastic constitutive model for sand is adopted. For the GREs built with dense and loose sand, most of the impact energy is dissipated by plastic deformation in the soil. Sand density has a dominant influence on the deformation and failure mechanism of GREs. During repeated impacts, elements near the impact location fail with increasing mean effective stress and Mises stress in dense sand. However, soil elements reach failure as the mean effective stress decreases and the Mises stress increases. There is much less deformation accumulation in GRE when the void ratio is lower as the soil has higher stiffness and shear strength. After multiple impacts, shear bands form in loose sand but strain localisation mainly occurs at the impact point for dense sand.