Determining soil shear strength parameters from CPT and CPTu data

Determining the soil shear strength parameters, i.e. cohesion (c), internalfriction angle () is done by means of laboratory tests and the in situ testing data. thecone penetration tests, cpt and cptu, are not only quick and economical, but alsorepeatable and show continuous records of soil parameters with depth. the commonapproaches for shearing strength parameters determination from cpt data are on thebasis of bearing capacity and cavity expansion theories. in this study, dierent methodsof soil shear strength parameters determination from cpt and cptu results, qc, fs andu, were reviewed and investigated. a new method is proposed for c,  prediction on thebasis of all quantities, qc, u and fs, from cptu considering bearing capacity mechanism offailure. one advantage of this method is improved accuracy in the case of erroneous databy using all three outputs of cptu. the proposed, current and experimental test results ofan information bank including 32 cpt and cptu results were assessed in ve sites. thecomparison of predicted and measured c and  angle values indicates good consistencyand low scatter for the proposed method. this can be led to more accurate and applicablecontinuous soil parameters in optimized geotechnical design.c 2013 sharif university of technology. all rights reserved.