In-situ assessment of the dynamic properties of municipal solid waste at a landfill in texas

An understanding of dynamic properties of Municipal Solid Waste (MSW) is essential for seismic response analysis of MSW landfills in areas of moderate to high seismicity. A field testing program aimed at characterizing the dynamic properties of MSW was executed at two locations in a Subtitle D landfill in Austin, Texas. Shear and primary wave velocities were measured using small-scale crosshole and downhole seismic tests. The combination of these seismic methods allowed an assessment of the effect of waste composition on dynamic properties, anisotropy, and Poisson׳s ratio of the MSW. In addition, steady-state dynamic testing was performed using two mobile vibroseis shakers to evaluate in-situ the nonlinear relationship between shear modulus and shearing strain. Horizontal steady-state shaking at increasing stress level generated shearing strains from 0.001% to 0.2% allowing evaluation of shear modulus reduction curves over a wide shearing strain range. The effect of confining stress on the dynamic properties of the MSW was also evaluated using the substantial weight of the vibroseis as reaction to apply surcharge vertical loads at the surface of the MSW.