Use of laboratory data to confirm yield and liquefied strength ratio concepts

Research output: Contribution to journalArticlepeer-review


A laboratory database of triaxial compression test results was collected to examine the use of strength ratios for liquefaction analysis. Specifically, the database was used to: (i) validate the yield strength ratio concept (or yield friction angle); (ii) demonstrate the parallelism of the consolidation line and steady state line of many sandy soils; and (iii) validate the liquefied strength ratio concept. The yield strength ratio of contractive sandy soils in triaxial compression ranges from approximately 0.29 to 0.42 (corresponding to yield friction angles of 16°-23°), while the yield strength ratio from flow failure case histories (which correspond approximately to direct simple shear conditions) ranges from 0.23 to 0.31 (or yield friction angles of 13°-17°). As expected, the yield friction angle is greatest in triaxial compression, smaller in direct simple shear, and likely smallest in triaxial extension. The steady state line and consolidation line of many contractive sandy soils are parallel for a wide range effective stresses, steady state line slopes, fines contents, and grain sizes and shapes that are applicable to many civil engineering structures. As such, the liquefied strength ratio is a constant for many sandy soils deposited in a consistent manner. The liquefied strength ratio is inversely related to state parameter and ranges from approximately 0.02 to 0.22 in laboratory triaxial compression tests. Flow failure case histories fall near the middle of this range.

Original languageEnglish (US)
Pages (from-to)1164-1184
Number of pages21
JournalCanadian Geotechnical Journal
Issue number6
StatePublished - Dec 2003


  • Collapse surface
  • Liquefaction
  • Liquefied shear strength
  • Penetration resistance
  • Steady state line
  • Yield shear strength

ASJC Scopus subject areas

  • Civil and Structural Engineering


Dive into the research topics of 'Use of laboratory data to confirm yield and liquefied strength ratio concepts'. Together they form a unique fingerprint.

Cite this