Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

Current practice (2009) for seismic analysis of embankment dams relies heavily on empirical correlations with penetration resistance (standard penetration test or cone penetration test) to predict the residual undrained shear strength of liquefied foundation materials. At least six such relationships have been published for the SPT alone, in different “formats.” Some apply a fines adjustment to the SPT blowcounts, but others do not; some express the predicted strength as a ratio with pre-earthquake effective overburden stress, whereas others predict it directly, without explicit consideration of overburden. For the foundations of embankment dams, the difference between the strength-ratio approach and prediction of Sur directly, from the SPT alone, can be important. In this paper, the underlying assumptions and data are reviewed critically, including the effects of different material types and different mechanisms governing the strength. Simplified statistical analyses were applied in attempt to determine the most appropriate format for a correlation and to obtain a new correlation that explicitly accounts for both overburden and blowcount.

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

On the Use of Empirical Correlations for Estimating the Residual Undrained Shear Strength of Liquefied Soils in Dam Foundations

San Diego, California

Current practice (2009) for seismic analysis of embankment dams relies heavily on empirical correlations with penetration resistance (standard penetration test or cone penetration test) to predict the residual undrained shear strength of liquefied foundation materials. At least six such relationships have been published for the SPT alone, in different “formats.” Some apply a fines adjustment to the SPT blowcounts, but others do not; some express the predicted strength as a ratio with pre-earthquake effective overburden stress, whereas others predict it directly, without explicit consideration of overburden. For the foundations of embankment dams, the difference between the strength-ratio approach and prediction of Sur directly, from the SPT alone, can be important. In this paper, the underlying assumptions and data are reviewed critically, including the effects of different material types and different mechanisms governing the strength. Simplified statistical analyses were applied in attempt to determine the most appropriate format for a correlation and to obtain a new correlation that explicitly accounts for both overburden and blowcount.