Constitutive model for municipal solid waste considering the effect of biodegradation

With large-scale construction of landfills, the study of the properties of municipal solid waste (MSW) has become an important subject. The objective of this study is to propose a new constitutive model for MSW considering the effect of biodegradation. The indicators representing the degree of biodegradation are first discussed, and the impact of biodegradation on the mechanical properties of MSW is then formulated in volumetric strain by introducing a biodegradation-induced void change parameter, which provides a fundamental understanding of the change in waste properties with long-term biodegradation. On the basis of this, a constitutive model is developed following the framework of critical state soil mechanics, and the proposed model is validated by comparing simulations and experimental data of triaxial tests and of a long-term settlement experiment. Finally, the effects of MSW composition and biodegradation are analysed by parametric studies.