Location

St. Louis, Missouri

Session Start Date

3-11-1991

Session End Date

3-15-1991

Abstract

The Spectral-Analysis-of-Surface-Waves (SASW) method is a seismic method for measuring in situ elastic moduli of layered systems, like soils or pavements. The inversion process associated with SASW can be an ambiguous task in certain cases, because a field dispersion curve needs to be matched with an unknown path through a family of theoretically defined curves for an assumed profile. A study of the influence of soil stratification on participation of higher Rayleigh modes in surface wave propagation included the evaluation of theoretical dispersion curves, modal shapes and rates of energy transmission in the horizontal direction. Wave propagation due to oscillations of a circular plate on the surface of layered systems was modelled and the resulting "simulated" dispersion curves compared with theoretical ones. The results indicate that higher Rayleigh modes can dominate wave propagation for all but a narrow range of low frequencies for profiles where softer layers are trapped between stiffer layers. Potential ways of identification of such situations are discussed and improvements of the inversion process suggested.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

Second Conference

Publisher

University of Missouri--Rolla

Publication Date

3-11-1991

Document Version

Final Version

Rights

© 1991 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 11th, 12:00 AM Mar 15th, 12:00 AM

Use of Rayleigh Modes in Interpretation of SASW Test

St. Louis, Missouri

The Spectral-Analysis-of-Surface-Waves (SASW) method is a seismic method for measuring in situ elastic moduli of layered systems, like soils or pavements. The inversion process associated with SASW can be an ambiguous task in certain cases, because a field dispersion curve needs to be matched with an unknown path through a family of theoretically defined curves for an assumed profile. A study of the influence of soil stratification on participation of higher Rayleigh modes in surface wave propagation included the evaluation of theoretical dispersion curves, modal shapes and rates of energy transmission in the horizontal direction. Wave propagation due to oscillations of a circular plate on the surface of layered systems was modelled and the resulting "simulated" dispersion curves compared with theoretical ones. The results indicate that higher Rayleigh modes can dominate wave propagation for all but a narrow range of low frequencies for profiles where softer layers are trapped between stiffer layers. Potential ways of identification of such situations are discussed and improvements of the inversion process suggested.