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Title: Inference of dynamic shear modulus from Lotung downhole data

Abstract

Downhole ground motions recorded at the Lotung Large-Scale Seismic Test (LSST) site were used in this paper to infer in-situ dynamic soil properties. The purposes were (1) to provide field evidence of nonlinear soil behavior during earthquake excitation; and (2) to evaluate the accuracy of dynamic properties obtained from geophysical measurements and laboratory tests. For each horizontal component and event analyzed, representative shear-wave velocity and effective shear strain (defined as 65% of peak strain) between consecutive recording stations were estimated. The representative shear-wave velocities were estimated from fundamental resonant frequencies identifiable from the Fourier spectral ratios. The effective shear strains were estimated by linear ground response deconvolution analyses based on the inferred shear-wave velocity profiles. The inferred reduction in shear modulus with increasing effective shear strain was compared with laboratory test data. The degree of agreement between the inferred shear modulus reduction curves and the laboratory test data varied with different testing programs. The inferred low-strain shear-wave velocity profile agreed with geophysical measurements. These observations not only provide field evidence of nonlinear dynamic soil behavior during earthquakes, but also confirm the reasonableness of data provided by geophysical measurements and laboratory tests.

Authors:
;  [1];  [2]
  1. Geomatrix Consultants, Inc., San Francisco, CA (United States)
  2. Electric Power Research Inst., Palo Alto, CA (United States)
Publication Date:
OSTI Identifier:
390058
Resource Type:
Journal Article
Journal Name:
Journal of Geotechnical Engineering
Additional Journal Information:
Journal Volume: 122; Journal Issue: 8; Other Information: PBD: Aug 1996
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; EARTHQUAKES; GROUND MOTION; SOIL MECHANICS; TAIWAN; ENERGY FACILITIES; SITE CHARACTERIZATION; SEISMIC EFFECTS; DAMS; EMBANKMENTS

Citation Formats

Chang, C Y, Mok, C M, and Tang, H T. Inference of dynamic shear modulus from Lotung downhole data. United States: N. p., 1996. Web. doi:10.1061/(ASCE)0733-9410(1996)122:8(657).
Chang, C Y, Mok, C M, & Tang, H T. Inference of dynamic shear modulus from Lotung downhole data. United States. https://doi.org/10.1061/(ASCE)0733-9410(1996)122:8(657)
Chang, C Y, Mok, C M, and Tang, H T. 1996. "Inference of dynamic shear modulus from Lotung downhole data". United States. https://doi.org/10.1061/(ASCE)0733-9410(1996)122:8(657).
@article{osti_390058,
title = {Inference of dynamic shear modulus from Lotung downhole data},
author = {Chang, C Y and Mok, C M and Tang, H T},
abstractNote = {Downhole ground motions recorded at the Lotung Large-Scale Seismic Test (LSST) site were used in this paper to infer in-situ dynamic soil properties. The purposes were (1) to provide field evidence of nonlinear soil behavior during earthquake excitation; and (2) to evaluate the accuracy of dynamic properties obtained from geophysical measurements and laboratory tests. For each horizontal component and event analyzed, representative shear-wave velocity and effective shear strain (defined as 65% of peak strain) between consecutive recording stations were estimated. The representative shear-wave velocities were estimated from fundamental resonant frequencies identifiable from the Fourier spectral ratios. The effective shear strains were estimated by linear ground response deconvolution analyses based on the inferred shear-wave velocity profiles. The inferred reduction in shear modulus with increasing effective shear strain was compared with laboratory test data. The degree of agreement between the inferred shear modulus reduction curves and the laboratory test data varied with different testing programs. The inferred low-strain shear-wave velocity profile agreed with geophysical measurements. These observations not only provide field evidence of nonlinear dynamic soil behavior during earthquakes, but also confirm the reasonableness of data provided by geophysical measurements and laboratory tests.},
doi = {10.1061/(ASCE)0733-9410(1996)122:8(657)},
url = {https://www.osti.gov/biblio/390058}, journal = {Journal of Geotechnical Engineering},
number = 8,
volume = 122,
place = {United States},
year = {Thu Aug 01 00:00:00 EDT 1996},
month = {Thu Aug 01 00:00:00 EDT 1996}
}