Use of EPS grains to simulate the behavior of MSW in simple shear

The difficulty in laboratory testing of highly heterogeneous municipal solid waste (MSW) may suggest an investigation of the influence of different stress/strain/drainage conditions, and use of an analogical equivalent medium such as assemblies of expanded polystyrene (EPS) grains, which are characterised by a mechanical response very similar to MSW but relatively simpler for testing preparation. Both materials in fact evidently show a behavioral analogy, such as a different response when subjected to triaxial compression or pure shear, resulting from the effects of significant porosity and a relevant inherent compressibility of the individual elements. This research is concerned with an experimental investigation into the behaviour of saturated assemblies of EPS grains, tested in the laboratory using a modified simple shear device. In addition to the description of the experimental testing technique, this paper attempts to discuss the main outcome of test results, showing particularly the influence of inherent compressibility of EPS grains on material volumetric response.