RESOLVED AND UNRESOLVED

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RESOLVED AND UNRESOLVED ISSUES IN SOIL
LIQUEFACTION by I. M. Idriss Department of
Civil Environmental Engineering University of
California, Davis, CA 95616-5294 e-mail
imidriss_at_aol.com Presented at US-Taiwan
Workshop on Soil Liquefaction Hsinchu,
Taiwan November 2 5, 2003
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AMONG THE REASONABLY RESOLVED ISSUES IS THE
SPT-BASED FIELD METHOD FOR ASSESSING TRIGGERING
OF LIQUEFACTION.
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Comparison of Curve Proposed by the
NCEER Workshop (1997) with that Originally
Constructed by Seed et al (1984) for Clean
sands Magnitude 7½ and s'vo 1 tsf (? 1 atm)
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Reevaluation of case histories of clean
sands published by Cetin et al (2000) Magnitude
7½ and s'vo 1 tsf (? 1 atm)
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Revised Values for Published Case Histories
of Clean Sands and Curve Proposed by
NCEER Workshop (1997) and Curve Derived in
2003 Magnitude 7½ and s'vo 1 tsf (? 1 atm)
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SPT-Based Relationships Published over the
Past 24 Years and the Revised Values for the
Published Case Histories for Clean
Sands Magnitude 7½ and s'vo 1 tsf (? 1 atm)
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Revised Values for Published Case Histories of
Cohesionless Soils with Fines Content Greater
than or Equal to 35 Magnitude 7½ and s'vo 1
tsf (? 1 atm)
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Equation for Clean Sands
Adjustment for Fines Content
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AN ISSUE THAT HAS YET TO BE FULLY RESOLVED IS
RESIDUAL STRENGTH
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Laboratory-Based Assessment vs Field-Based
Assessment
Sr Independent of s'vo vs Sr / s'vo
Adjustments for Fines Content
Extrapolation to Larger Values of Blow Count