Shear strength testing of intact and recompacted samples of municipal solid waste

Abstract

This paper presents results of shear strength testing of intact and recompacted samples of municipal solid waste (MSW). A method for in situ sampling of MSW from landfills using a push-in sampler was developed and used to obtain intact samples of MSW from a large municipal landfill. Shear strength testing of MSW was carried out using a large triaxial compression apparatus as well as a large direct shear apparatus. The results are presented in terms of cohesion intercept (c′) and angle of shearing resistance ([Formula: see text]) and are compared with those available in published literature. Based on these results and their favourable comparison with this literature, it can be concluded that meaningful shear strength parameters for MSW can be obtained using consolidated undrained triaxial tests on large-diameter intact and recompacted samples. A fairly consistent picture of the shear behaviour of MSW obtained from effective stress paths in triaxial tests appears to suggest that shear behaviour of MSW can be explained using the effective stress principle. It is suggested that recompacted samples could be used for obtaining reasonable estimates of c′ and [Formula: see text] for MSW; however, it may be necessary to use intact samples to establish the pre-failure deformation behaviour of MSW.