A constitutive model for geosynthetic interfaces considering nonlinear softening behavior

Abstract

Geosynthetic interfaces within composite liner systems usually play an important role in failure events of landfills and should be well considered in stability assessment. A constitutive model based on the disturbed state concept is proposed to describe the shear behavior of geosynthetic interfaces under both static and dynamic conditions. The interface behavior is assumed to be governed by two states, i.e. the intact state and the fully disturbed state. The intact state is described with a bounding surface model with vanishing elastic range which has the advantages of a concise mapping rule and fewer parameters, and the fully disturbed state is characterized by a nonlinear strength envelope. The two states share the same normal stress, but the macro shear stress of the geosynthetic interface is the coupling result of the two states through a disturbance function related to accumulative plastic shear displacement. The model performs well in describing the monotonic shear behavior of typical geosynthetic interfaces for different drainage conditions and stress paths. Furthermore, a series of cyclic shear tests and shaking table tests on typical geosynthetic interfaces are also modeled, and the results indicate that the dynamic response and softening behavior can be well described with this model.