Extended phase relations and load effects in MSW.

The moisture retention and compression characteristics of municipal solid waste under self-weight are likened to those of an unsaturated soil. By assuming that the solid organic fraction in waste retains a relatively immobile micropore moisture and that deformation at low confining stress occurs at the expense of a relatively large macropore system, an insight into the variation of density and moisture with depth can be gained. With data on the composition of the waste, the phase composition can be extended to distinguish between solid organic and solid inorganic fractions, resulting in a four phase material model. The model is developed using detailed moisture and waste composition data from the Lyndhurst Sanitary Landfill site in Victoria, Australia. Finally, comparison of the model with large scale compression test results provides an insight into the nature of waste compression and moisture content data at low confining stress.