by Norwest Holst soil engineering technical director Matthew Baldwin and Soil Mechanics technical manager Dick Gosling. This paper was first published in GE’s August 2009 issue.
General guidance on geotechnical sampling has been part of BS 5930, both in its 1981 and 1999 editions. Within this standard, the UK geotechnical community has been able to find information on sampling methods and sample types. BS EN ISO 22475-1, which was first published in 2006, is titled Geotechnical investigation and testing - sampling methods and groundwater measurements. Together with other standards, it is a normative reference cited in BS EN 1997-2, that is, Eurocode 7 Part 2 (EC7-2), published in 2007.
Unlike the existing BS 5930, which is a code of practice, 22475-1 has the full status of a British Standard. Implementation of 22475-1 into UK practice should be in progress and could be complete during 2009. While much of 22475-1 describes the various methods for the sampling of the ground, it also reiterates the quality classes defined in EC7-2 that relate to each sampling type. It is this issue of quality that is likely to be problematic for the UK geotechnical industry.
This paper compares the general philosophy of BS 5930 with 22475-1 and makes comment on how geotechnical sampling in the UK may be affected in the near future. Some recommendations are also made as to possible solutions to help address the potential problems that the new standard has thrown up.