Estimating the undrained strength of sand: a theoretical framework

• Author(s) / Creator(s)

  • Fear, C. E.
  • Robertson, P. K.

• Abstract: A framework for estimating the ultimate undrained steady state shear strength of sand (S-u) from in situ tests, which combines the theory of critical state soil mechanics with shear wave velocity measurements, is presented. For a particular direction of undrained loading, samples of a given sand at a constant void ratio will reach the same S-u, despite the magnitude of the initial effective confining stresses. Unique S-u/p' or S-u/sigma'(v) ratios for a given direction of loading exist for a particular sand only if state parameter is constant throughout the deposit. Normalized shear wave velocity, V-s1, can be correlated with void ratio and is therefore used to estimate S-u for a given initial state and direction of loading. Strengths in triaxial compression are examined in this paper; however, the same framework can be used to estimate strengths under other directions of loading. The S-u-V-s1 relationship is shown to be relatively sensitive and should be used more as a screening tool rather than an accurate means of predicting S-u. V-s1 is converted to equivalent values of SPT (N-1)(60) and CPT q(c1), and the results are compared with the current methods of estimating S-u.

• Date created

  1995

• Subjects / Keywords

  • Sand
  • Liquefaction
  • In situ testing
  • Undrained Strength

• Type of Item

  Article (Published)

• DOI

  https://doi.org/10.7939/R3J678Z7S

• License

  © 1995 NRC Research Press (Canadian Science Publishing. This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited.