Cyclic Characterization of OII Landfill Solid Waste

Abstract

As part of predesign studies for closure of the Operating Industries, Inc. (OII) landfill Superfund site, field and laboratory studies were combined with back analyses of strong motion data to characterize the behavior of the OII solid waste when subjected to strong earthquake shaking. Small strain shear modulus values for the solid waste material were established on the basis of field measurements of shear wave velocity and unit weight. Large-diameter (457 mm) cyclic direct simple shear (CyDSS) testing was performed on reconstituted solid waste specimens to investigate the modulus reduction and damping characteristics of solid waste at large strains. Results of two-dimensional finite element back analyses of strong motion data recorded at the site were combined with the results of CyDSS testing to establish solid waste modulus reduction and damping curves over the range of cyclic shear strain required for site closure design. One-dimensional deconvolution of motions recorded on fill at the base of the landfill was an essential step in the two-dimensional finite element back analyses of strong motion data. The resulting modulus reduction and damping curves indicate that OII solid waste is a fairly linear material in the small to intermediate strain range, but that a significant reduction of shear modulus occurs when the cyclic shear strain exceeds approximately 0.1%.