A binary-medium-based constitutive model for artificially cemented gravel-silty clay mixed soils

Abstract

In situ soils of deep overburden layer of dam foundation are widely distributed in Southwest China, which are mixtures of gravel and silty clay in varying proportions and have cementation feature between soil particles. Based on a series of triaxial compression tests carried out on artificially cemented mixed soils (CMS) and remolded mixed soils (RMS) at confining pressures of 50, 100, 200 and 400 kPa with fine contents (silty clay) of 13%-70% in mass, a binary-medium constitutive model for artificially cemented mixed soils is proposed within framework of breakage mechanics theory for geological materials and homogenization theory. This model was formulated by regarding the soils as a binary medium consisting of bonded blocks (idealized as bonded elements) and weakened bands (idealized as frictional elements), whose deformation properties are described by the modified Duncan-Chang model and the Lade-Duncan elastoplastic model, respectively. The non-uniform distribution of stress and strain within a representative volume element can be given by introducing the structural parameters of breakage ratio and local stress coefficient. Comparisons of computed results with test results demonstrate that the binary-medium constitutive model can reflect mechanical properties of artificially cemented mixed soils well.