Sampling Disturbance in Soft Ground: Implications in Geotechnical Design

This paper discusses the main mechanisms of sampling disturbance in soft ground and their implications in geotechnical design. In addition to the mechanical disturbance associated with the type of sampler, the influence of other factors frequently overlooked in practice such as thermal loading due to waxing as well as biological effects due to long-term storage, are evaluated. The paper discusses three methodologies for assessing sample quality in soft soils, which may be easily incorporated in practice. In the last section, mechanical soil properties derived from specimens retrieved using four different samplers are used in the prediction of the total settlement and excess pore water pressure underneath an embankment. The results of the prediction exercise demonstrate the negative effects of poor sampling in geotechnical design. It demonstrated that reliable and cost-effective predictions of geotechnical infrastructure are possible with minimum improvements to the current practice for sampling and testing of soft clays.