The second james k. mitchell lecture undisturbed sand strength from seismic cone tests

Abstract

During routine site investigations, high-quality sampling and laboratory testing of sands are not feasible because of inevitable sample disturbance effects and budgetary constraints. Herein, a select database is compiled for calibration of cone penetration test (CPT) interpretative methods, primarily from undisturbed frozen sand samples at 15 sites in Japan, Canada, Italy, Norway, and China. The database is used to evaluate the peak secant friction angle (Formula presented.) in terms of the normalized cone tip resistance (Formula presented.) using two analytical approaches: (i) spherical cavity expansion theory with an operational rigidity index (Formula presented.), and (ii) a limit plasticity formulation with appropriate angle of plastification (Formula presented.). Backfigured values of (Formula presented.) and (Formula presented.) are found correlated to the normalized small-strain stiffness (Formula presented.). Thus, with measurements taken of both the initial shear modulus and shear strength, seismic cone tests offer the opportunity to derive the entire stress–strain–strength response of sands at all depths. © 2006 Taylor & Francis Group, LLC.