A comparative study on CPTu-based soil classification methods: Case studies

This paper presents a comparative study on the applicability of three CTPu-based soil classification charts, namely, Robertson’s normalized (SBTn) chart (Robertson 2009), Eslami-Fellenius (EF)’s non-normalized chart (Eslami and Fellenius 1997) and Robertson’s non-normalized (SBT) chart (Robertson 2010). A well-monitored database of CPTu data at six study sites of different geological conditions was used for the analyses. It is found from the study that when the effective stress (σʹv0) is small, typically smaller than 150 kPa, the EF’s and Robertson’s SBTn charts results in similar soil types obtained from visual classification procedure (VCP) whereas the Robertson’s SBT chart results in similar or slightly coarser soil types. When the σʹv0 becomes larger, the Robertson’s SBTn chart still results in soil types well matched with those obtained from the VCP but both the non-normalized charts tend to result in coarser soil types. This feature of the non-normalized charts is more pronounced in stiff clayey or dense sandy soils. © 2022 the Author(s).