Dick Gosling, technical manager, Soil Mechanics Matthew Baldwin, technical director, Norwest Holst Soil Engineering. This paper was first published in GE’s March 2010 issue.
In a technical note published in the August 2009 issue of Ground Engineering (Vol 42, No 8) the authors summarised the implications for the UK geotechnical industry of sampling requirements contained in BS EN ISO 22475-1:2006. In particular, they drew attention to the UK’s traditional open drive tube sampler (U100), which has been used extensively by the site investigation sector.
The U100 is a thick-wall open tube (OS/TKW) sampler as defined in 22475-1, and as such it does not comply with the criteria in that standard for obtaining quality class 1 samples (of cohesive material). Thus, adherence to 22475-1 will preclude samples recovered with this equipment from being used for strength and compressibility testing in the laboratory.