Evaluation of existing CPT correlations in silt

Abstract

This paper evaluates the applicability of existing Cone Penetration Test (CPT) soil type and soil properties correlations in two different deposits of uniformly graded non-plastic silt. Current CPT correlations for soil engineering properties are based largely on experience in either sands that are typically drained during penetration, or clays that are typically undrained. Silts may exhibit partially drained conditions during penetration that introduces uncertainty when applying correlations from the literature. The assessment is based on an analysis of existing CPT data collected at two study sites in Rhode Island, U.S.A. that are underlain by thick deposits of non-plastic silt. Existing CPT correlations were used to predict the soil type and selected geotechnical properties of the silt, which were compared to laboratory test results to evaluate the quality of the predictions. The silts in this study exhibited partially drained to drained behaviour during cone penetration. Existing CPT soil classification charts were ineffective in identifying the silt but correctly characterized its engineering behaviours. Existing CPT correlations accurately predicted the friction angle, shear wave velocity, and cyclic resistance of the silts investigated in this study.