Two mechanisms in reinforced soil structures subjected to seismic forces

Abstract

Internal stability analysis of reinforced soil structures assumes different failure surface generally applicable to geosynthetic reinforcement and steel reinforcement, considering those as extensible and inextensible, respectively. The same assumption is applicable to seismic design too. However, a wall reinforced with geosynthetic reinforcement of high stiffness or small spacing and comparatively rigid facia can depict behaviour similar to walls reinforced with inextensible reinforcement. It is imperative to understand this behaviour and see applicability of different mechanisms depending on relative extensibility of reinforcements during seismic loading. A 2D Finite Element model of a wrap-around reinforced soil structure is developed in OpenSees and subjected to seismic forces. Analysis is focused on the development of failure plane, defined on the basis of the locus of maximum reinforcement forces. The reinforcements with low stiffness in general showed a failure plane that follows Rankine’s active condition and with relatively high stiffness it showed roughly vertical failure mechanism. The locus of maximum reinforcement forces was also observed to be coincident with the zone of localized shear strains. These observations are useful in developing guidelines for safe and economical seismic design of reinforced soil structures.