Characterization of an organic soil deposit using multi-faceted geotechnical field and laboratory investigations

Abstract

The findings from a comprehensive characterization of an organic soil deposit using multi-faceted geotechnical field and laboratory investigations are presented. The field-testing program comprised cone penetration testing (SCPT) with shear wave velocity (Vs) measurements, full-flow ball penetration testing (BPT), and electric vane shear testing (eVST). The work was supplemented by a laboratory program comprising index testing, one-dimensional consolidation testing, and direct shear testing conducted on the tube and disturbed soil samples obtained from the site. Data originating from this wide range of testing tools deployed at a single site provided a unique opportunity to get insights into the strength and stiffness properties of organic soils and examine possible correlations between such properties and test measurements. The work confirmed the suitability of BPT for characterizing organic soils due to its ability to mobilize/test a larger representative volume of soils during penetration, thereby reflecting a practical average response for the tested soil mass. It was possible to develop simple correlations to directly estimate the small-strain stiffness (Gmax) and undrained shear strength (Su) of organic soils using data from BPT. With these capabilities, combined with the simplicity and the relatively easy field deploy ability, BPT emerges as a tool with high applicability for the geotechnical characterization of organic soils - an activity essential to support the design of buried energy pipelines that traverse over large distances in remote muskeg terrains in Canada.