Research Prior to 2008

• Identification of Landfill Properties during Earthquakes (Bardet). The performance of landfills during strong earthquake shaking is a matter of considerable concern, deserving to be studied more extensively than it has been. In this research, we investigate the dynamic properties of a particular landfill using strong motion recordings, available field measurements, and simplified physical models. The results of this study are useful to analyze the dynamic response of landfills and cap systems during low to moderate size earthquakes. We recommend the deployment of more field instruments on landfills to document their dynamic response during future earthquakes, and to develop large-scale laboratory tests to determine landfill material properties under large static and dynamic strains.
• Strong Motion Vertical Array in LA Area (Bardet).This project evaluates site response at vertical seismograph arrays at Cerritos College in Norwalk and downtown San Bernardino, California. The seismic response at the sites are calculated using borehole lithologic and geotechnical data already available for the sites, together with linear, equivalent linear, and fully nonlinear one-dimensional dynamic site response codes. The purpose of this project is a blind experiment to test the adequacy of existing dynamic soil response codes, strain-dependent shear modulus reduction curves, and strain- dependent damping curves to predict soil response for typical Los Angeles basin site conditions.
• Database of Case Histories of Liquefaction-Induced Deformation during Earthquakes (Bardet).The research objective is to update the database of case histories of liquefaction-induced ground deformation which have been developed at USC. This database is intended to assemble data required for developing deterministic and probabilistic models of liquefaction-induced ground displacement. The case histories are focused in the range of displacement of interest to lifelines engineering.
• Development of a Virtual Geotechnical Data Center (Bardet).The long-term research objective is the creation of a virtual geotechnical data center, which archives the data generated by researchers and practitioners in geotechnical engineering and distributes it by the means of the Internet. The present research objective is to adapt and apply available client/server database technologies for distributing geotechnical information over the Internet, including definition of RDBMS data structures and data standards, guidelines and software for data entry of geotechnical data, and distribution of geotechnical data by the means of internet and GIS Map Servers.
• Seismic Design of Bridges - Evaluation of Pile Group Stiffness (Martin). Uncertainties presently exist in the determination of the lateral stiffness of large groups of closely spaced piles for use in earthquake response analysis of bridges. This research is examining the use of three dimensional finite difference analyses to evaluate the effects of soil-pile interaction on lateral stiffness for closely spaced piles subjected to cyclic loading, together with methods to extrapolate simplified design methods for single piles to pile groups.
• Soil-Foundation Structure Interaction (Martin). The objectives of this research project are to (a) prepare a state-of-the-art report discussing the role of shallow foundation interaction on the seismic response of structures and to (b) develop an improved nonlinear load-deformation model for vertical, moment and shear loading of shallow foundations under cyclic loading. This model will be used with structural analysis codes to study the influence of nonlinear foundation response on the earthquake response of structures.
• Foundation Design for Liquefaction Induced Lateral Displacement (Martin). This study involves evaluating and developing models to simulate the interaction between soil, in a liquefaction induced lateral spread zone, and pile or pier foundation elements including pile caps, which support bridge structures. Specific attention will be paid to capacity simulation for foundation elements
• Evaluation of Ground Remediation Techniques (Martin). As a part of a comprehensive program of research to develop seismic design guidelines for bridges, experimental and analytical research is being conducted to evaluate and improve design approaches for the use of ground improvement techniques to prevent earthquake induced liquefaction. Specific studies are focusing on stone column and compaction grouting methods as applied to both sand and silts and the use of deep soil-cement mixing techniques.
• Geotechnical Applications of Biopolymers (Martin). The potential application of biopolymer technology for the construction of impervious barriers, using silty soils, is being investigated. Laboratory experiments to date, demonstrate that the permeability of silty soils can be reduced by a factor of 100 or greater. This can be done by either mixing commercially available biopolymers such as xanthan gum with the soil matrix or slime-forming microorganisms with the soil matrix to produce biopolymers. Experimental results indicate that the soil shear strength is also increased by up to 50 percent. The practical application of the technology to construct impervious landfill covers is presently being evaluated.

The Faculty

Selected Publications