Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

A new method for evaluating spatial variability of soil strains during earthquakes is developed. The idea is based on electrical resisitivity concepts. By solving the classic Maxwell’s equations applying Green’s function for the boundary conditions, we obtained a closed form solution relating the electric potential measurements to the soil’s displacements during earthquakes. The displacement information can be further used to obtain soil strains. In centrifuge models, the displacement measurements using an electrode switching system have been demonstrated to have spatial and temporal resolutions of 1 mm and 1 ms. Based on the high resolution of the displacement that is obtainable, strains of the soil matrix can be computed. The scheme of the method is to establish electromagnetic fields in saturated soil by injecting low-frequency alternating currents through electrodes in a designed mesh and the displacement of the soil is related to the change of electrical potential measured on the electrode located at that point. The viability of the technique is demonstrated by measuring the liquefaction-induced displacements of objects in a geotechnical centrifuge model test. This method is considered to be a useful technique for monitoring strain distributions in physical centrifuge models and has practical application potentials in the field.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

A New Method for Evaluating Spatial Variability of Soil Strains Developed during Earthquakes Based on Electrical Resistivity Concepts Using Green’s Function

San Diego, California

A new method for evaluating spatial variability of soil strains during earthquakes is developed. The idea is based on electrical resisitivity concepts. By solving the classic Maxwell’s equations applying Green’s function for the boundary conditions, we obtained a closed form solution relating the electric potential measurements to the soil’s displacements during earthquakes. The displacement information can be further used to obtain soil strains. In centrifuge models, the displacement measurements using an electrode switching system have been demonstrated to have spatial and temporal resolutions of 1 mm and 1 ms. Based on the high resolution of the displacement that is obtainable, strains of the soil matrix can be computed. The scheme of the method is to establish electromagnetic fields in saturated soil by injecting low-frequency alternating currents through electrodes in a designed mesh and the displacement of the soil is related to the change of electrical potential measured on the electrode located at that point. The viability of the technique is demonstrated by measuring the liquefaction-induced displacements of objects in a geotechnical centrifuge model test. This method is considered to be a useful technique for monitoring strain distributions in physical centrifuge models and has practical application potentials in the field.