Modelling and comparing 3-D soil stratigraphy using subsurface borings and cone penetrometer tests in coastal Louisiana, USA

Abstract

ABSTRACTComplex subsurface geology of coastal Louisiana, formed under fluvial, deltaic, and sea level influences, increases the uncertainty in design and construction of hard and natural infrastructure. In this study, twenty-four (24) collocated soil borings and CPTs at the Inner Harbor Navigation Canal (IHNC) in New Orleans, Louisiana were used to construct multiple three-dimensional (3-D) soil stratigraphy models by ordinary kriging. To explore the spatial distribution of soils at the site, four soil stratigraphy models were established, including the unified soil classification system (USCS) from borings and three constructed using soil behaviour type (SBT) correlations. The SBT correlation using friction ratio () and corrected cone resistance () was found to better represent organic soils pervasive in coastal Louisiana compared using normalised friction ratio with normalised cone resistance, and using soil classification boundary. The comparison shows that the normalisation of sleeve resistance translates the data to higher normalised friction ratio compared to values. The boring and CPTu sounding comparisons suggest that extending the from 8% to 20% in the Rf–qt chart to better capture the organic-rich soils in coastal Louisiana.