Elastoplastic model for cemented soils

This paper presents a model for bonded or cemented soils within the framewo rk of hardening plasticity. The model is based on the concepts that (1) the strength of a cemented soil can be considered to be made up of two compone nts, the usual strength of the soil skeleton and the strength of cementatio n bonds; and (2) the deformation of the soil is associated with the compone nt of stresses on the soil skeleton (excluding the bonds), as in a reconsti tuted soil, whereas the cement bonds offer additional resistance at any giv en strain level. The overall response of the soil under loading can be visu alized as two stiffnesses acting in parallel for the given unit strain. Sep arate stress-strain relations are defined for the two components and they a re then combined to give the overall response. The stress-strain relationsh ip for the soil skeleton component is described here using the modified Cam -clay model. A simple model within the elastoplastic framework is proposed for the "cemented" component. The cemented component incorporates strain so ftening. The input parameters required are minimal, well defined, and easil y determined. The model predictions are compared with test data of several soils under drained and undrained triaxial conditions.