Effect of cone penetrometer type on CPTU results at a soft clay test site in Norway

Abstract

Seven different cone penetrometers from 5 manufacturers have been used in a comparative testing program at the Norwegian GeoTest site (NGTS) on soft clay in Onsøy, Norway. Tests with all cone types give very repeatable penetration pore pressure, u2. When comparing tests with different cone types, six of the cones give very similar u2 values. One cone type give consistently higher u2 values. Measured cone resistance, qc, generally varies somewhat more, both regarding tests with the same cone, and when comparing results of one cone type with another. Some of the cone types give good repeatability for sleeve friction, fs, readings, while some show relatively large variation. When comparing fs from different cone types the variation is quite large, which is in line with previous experience. An attempt has been made to understand the reasons for the large fs variations.

Effect of cone penetrometer type on CPTU results at a soft clay test site in Norway