Location

San Diego, California

Session Start Date

3-26-2001

Session End Date

3-31-2001

Abstract

This paper provides a method for estimating the non-stationary variations of rigidity and damping of soils related intimately to the non-linear earthquake responses of ground. This method uses the concept of the “Complex Envelope” to inversely estimate soil rigidity and damping from the time histories of stress and strain induced in soils. It is quite different from the conventional method, which uses graphical technique for the stress-strain orbit, in the point of quantitatively estimating the time-dependent variations of soil rigidity and damping. The validity of the method is first discussed using theoretical derivations and numerical simulations. It is then applied to the down-hole array records of strong motions obtained at Port Island during the 1995 Kobe Earthquake, Japan. The analyzed results showed that some extreme reductions of soil rigidity occurred in the superficial layers during the mainshock of the earthquake, depending strongly on strain behaviors.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-26-2001

Document Version

Final Version

Rights

© 2001 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 26th, 12:00 AM Mar 31st, 12:00 AM

A Method for Estimating Non-Stationary Variation of Soil Rigidity During Strong Motions

San Diego, California

This paper provides a method for estimating the non-stationary variations of rigidity and damping of soils related intimately to the non-linear earthquake responses of ground. This method uses the concept of the “Complex Envelope” to inversely estimate soil rigidity and damping from the time histories of stress and strain induced in soils. It is quite different from the conventional method, which uses graphical technique for the stress-strain orbit, in the point of quantitatively estimating the time-dependent variations of soil rigidity and damping. The validity of the method is first discussed using theoretical derivations and numerical simulations. It is then applied to the down-hole array records of strong motions obtained at Port Island during the 1995 Kobe Earthquake, Japan. The analyzed results showed that some extreme reductions of soil rigidity occurred in the superficial layers during the mainshock of the earthquake, depending strongly on strain behaviors.