Seismic Response Characteristics of Municipal Solid Waste Landfills

Abstract

As a new type of geo-engineering, municipal waste landfills had a number of characteristics, such as low density, high compressibility of MSW and existence of liner system, which distinguished them from natural slopes and other types of artificial dams. In order to investigate the seismic response characteristics of landfills, 8 physical model experiments of landfills were conducted on shaking table, and nonlinear numerical simulation for the test were performed subsequently. The experimental results and numerical calculation could verify and supplement one another, and also indicated that experiencing excessive relative displacement between the specific interfaces within base and cover liners was primary failure patterns of landfill under earthquake. However, waste itself collapse was seldom a concern problem. There were obvious two parts of wedges named “active wedge” and “passive wedge”, while landfill cover slop sliding. Further results could also be got: (1) the landfill height, density of MSW and spectral characteristics of input motions were the primary factors that effected acceleration response at the top of landfill. (2) Significant acceleration attenuation of a motion could occur when earthquake wave transferred through landfill base liner containing HDPE geo-membrane. Furthermore, larger acceleration was the input motion, more obvious was the attenuation. (3) The inclination angle of landfill cover had significant effects on the critical sliding of cover liner. However, the friction coefficient of the HDPE interface within the bottom liner system was the primary factor effecting the critical sliding acceleration of bottom liner system with relatively small base slope angle.