Reliability of CPT I_c as an index for mechanical behaviour classification of soils Available to Purchase

This paper presents results of an analysis of a set of high-quality, side-by-side piezocone penetration test (CPTu) and standard penetration test (SPT) data for examining mechanical behaviour-based classification of soils. The results show that the soil behaviour type index (I_c), either defined by Jefferies and Been (denoted herein as I_c,BJ) or by Robertson and Wride (denoted herein as I_c,RW), is an effective parameter for mechanical behaviour classification. Additionally, an effort is made to find the most suitable I_c cut-off (or boundary) value that can delineate cohesionless (sand-like) soils from cohesive (clay-like) soils. The Robertson and Wride's formulation, I_c,RW = 2·67 is found capable of delineating these two classes of soils. Similarly for the Been and Jefferies' formulation, I_c,BJ = 2·58 is found to be the most suitable I_c cut-off value for such classification purpose. These cut-off I_c values for distinguishing sand-like soils from clay-like soils are found to be reliable in a case study of liquefaction susceptibility.