| As part of a collaborative NSF-funded research program a comprehensive investigation of the static and dynamic properties of Municipal Solid-Waste (MSW) was performed. The investigation included drilling activities at the Tri-Cities landfill located in Fremont California, in-situ testing, sample collection, waste characterization and an extensive, primarily large-scale, laboratory testing program of municipal solid-waste. This thesis summarizes the in-situ testing and drilling operations that were performed at the Tri-Cities landfill, as well as the waste characterization of bulk samples collected from the Tri-Cities landfill. It also presents the results of the laboratory testing program performed at the University of California at Berkeley and the University of Patras, Greece.;A comprehensive primarily large-scale triaxial laboratory investigation was performed at the University of California at Berkeley. Twenty-nine large-scale (30 cm diameter, 60-63 cm nominal height) triaxial samples of MSW were prepared using three waste samples from the Tri-Cities landfill, varying in age from 2 to 15 years old and sampled from different depths. A total of 26 large-scale monotonic triaxial tests have been performed to evaluate the monotonic stress-strain response of MSW in triaxial compression, triaxial extension, and triaxial compression-unloading. Additionally, more than 80 large-scale cyclic triaxial tests have been performed to evaluate the dynamic properties (small-strain shear modulus, normalized shear modulus reduction, and material damping) of MSW. The effects of waste composition, unit weight, confining stress, time under confinement, loading frequency and strain-rate were studied to evaluate the static and dynamic properties of MSW. In addition to the tests performed at UC Berkeley, an extensive large-scale (30 cm x 30 cm x 18 cm) direct shear testing program was performed at the University of Patras, using the same waste material, the same specimen preparation techniques, and with some direction from the UC Berkeley research team.;Based upon analysis of available field data and large-scale laboratory data, most of which have been generated as part of this research study, a characteristic MSW unit weight profile represented by a hyperbolic equation was found to exist for individual landfills. The available data indicate that MSW unit weight is governed by the waste composition and compaction effort applied when first placed, and the effective confining stress currently acting on it, which is largely a function of its current depth in the landfill. A hyperbolic model that captures these key factors in estimating the unit weight of MSW at a specific landfill has been developed and calibrated with the available field data. Guidelines for developing a reliable MSW unit weight profile for a specific landfill under three likely design scenarios have been provided. (Abstract shortened by UMI.). |
