Seismic yield accelerations of MSW landfills by pseudo-dynamic approach

Abstract

Estimation of seismic yield acceleration for the municipal solid waste landfills is the basic step for design to mitigate the hazard of earthquake on landfills. For most of the landfills constructed in the seismic zones, influence of the vertical component of seismic acceleration is often neglected assuming that it is not in phase with the horizontal seismic acceleration and hence does not affect the design parameters largely. Conventional pseudostatic analysis using limit equilibrium method does not consider the variation of seismic inertial forces with time and also effect of vertically propagating shear and primary waves, which can have serious effect on the design values. To overcome the limitations of existing methodology, in the present study, pseudo-dynamic approach, which takes into account the effects of time, primary and secondary waves, frequency of excitation, is applied for the first time for dynamic analysis of landfills for three different typical practical geometries of landfills. Chosen sets of landfills resemble some of the existing landfill geometries. Design equations and charts are developed for factor of safety against base sliding and seismic yield acceleration for these three typical landfill geometries. The results are compared with the similar results obtained by using conventional pseudo-static analysis, and the influence of vertical seismic acceleration on factor of safety against base sliding and yield acceleration is reported.