On-site characterisation of loessic deposits in Kent, UK

Abstract

A detailed site characterisation was undertaken in order to assess methods that could be used to determine the depth and lateral extent of a potentially collapsible loessic brickearth deposit at a site in Kent. The investigation presented in this paper covers both geotechnical and geophysical evaluations, correlated to detailed lithological logs of trial pits at the site. This enabled cone penetrometer profiles to be compared directly with a suite of rapid geophysical survey techniques, which included electromagnetic (EM31 and EM34), electrical resistivity surveys and shear wave profiles, calibrated against the same soil profile. From this it was possible to determine the variability and extent of a collapsible loessic soil across the entire test site, thus demonstrating that appropriately calibrated geophysical techniques can provide a rapid indication of the presence at depth of a potentially unstable soil.