Determination of chalk structure using cone penetration tests

As part of a large development underlain by the Newhaven Chalk Formation to the northeast of Brighton, England, geotechnical investigations have been undertaken to, amongst other objectives, classify the chalk and define a 3D surface of the top of the structured material. This was a key parameter for the various design elements of the project, as the structured material was targeted to form the founding layer for many of the shallow building foundations and other structures on the site. A large number of cone penetration tests (CPTs) were also undertaken over the site. This paper compares recorded CPT parameters to a number of adjacent reference boreholes, and also the interpolated 3D top of structured chalk surface, with an aim of allowing cone penetration tests to potentially be used to determine the boundary between structured chalk and structureless chalk on other sites. Published historical relationships of various CPT parameters are also compared with the data gathered from site.