Laboratory-based assessment on similarities between dynamic behavior of MSW and clay

The dynamic response of landfills under seismic loads is greatly dependent on stress–strain cyclic characteristics of municipal solid waste (MSW). Accurate evaluation of these characteristics is essential for improving the current understanding of MSW’s seismic behavior and, consequently, stabilizing landfills under such loads. Therefore, a comprehensive undrained cyclic triaxial test program was executed to examine the MSW's dynamic response under influential factors such as the number of loading cycles, loading frequency, confining stress, and aging. Additionally, this study focuses on finding similarities between normalized shear modulus and damping ratio curves of MSW and clayey soil. Based on the results of the current investigation and those obtained from the literature, the progression of decomposition in organic content of MSW and compaction induced by landfill operations improves the uniformity of MSW. This improvement in uniformity decreases the MSW's discreteness and, consequently, results in a higher amount of shear stiffness under cyclic loadings. However, the damping ratio results are not following a specific trend due to the unknown nature of MSW. Given the observations made by this study, MSW behaves similar to moderately plastic clay. This finding was assessed further by comparing the influential factors’ effect on MSW and clayey soil’s dynamic responses.