CPTU-based permeability evaluation of clays

Abstract

The piezocone penetration test (CPTU) is an efficient in-situ testing method for delineating subsurface stratigraphy and interpreting geoparameters continuously with depth. However, owing to the regional sensitivity and geological diversity, the applicability of CPTU-based geotechnical parameter evaluation methods is limited when applied to specific sites. This requires further scrutiny considering the different geological histories and local soil conditions. In this study, a database that included a collection of CPTU test sites in Jiangsu Province, China, was compiled containing high-quality sampling and laboratory testing performed to characterize the permeability of clay soils. Several published CPTU correlations for determining soil permeability were summarized and compared with laboratory-measured soil permeability as a benchmark reference. The evaluation results indicated that the I c-based correlations can provide a reasonably good determination of the permeability for the investigated soils with root mean squared error of 0.89 and mean absolute error of 0.77. Finally, a modified approach was presented to evaluate the permeability coefficient of Jiangsu clay soils, which was calibrated using two additional case studies.