Existing industry standards and guidelines present different procedures for measuring maximum (p/sub max/) and minimum (p/sub min/) dry densities of sand. A comparison study by Lunne et al. (2019) showed that the p/sub max/ and p/sub min/ values are highly method dependent and concluded that there was a need to develop new robust procedures for the determination of p/sub max/ and p/sub min/. The new procedures should give consistent results for a range of sands without introducing grain crushing when carrying out the determination of p/sub max/. The procedures should further minimise the amount of sand required for testing, which is often limited especially in offshore investigations. This paper describes recent work undertaken to develop such a set of procedures. Initial phases and subsequent continued development at Geolabs and NGI were performed followed by validation testing through trials at four other laboratories. Testing was undertaken initially on two sands with negligible fines contents and then two further sands with 10-14% fines content. Robust procedures have been developed for both p/sub max/ and p/sub min/ measurements which have been validated against comparisons with a wider range of sands from the earlier study. It is proposed that the methods developed in this work should be taken forward as a sound basis for future specifications and ultimately International standards.
Siren Knudsen, John J. M. Powell, Tom Lunne, Nanna V. Thomsen, Lone Krogh and Andy Barwise
Keywords: laboratory tests, standards, maximum and minimum dry densities, density determinations, relative density
Publisher: DFI