Continuous Characterisation of Near-Surface Soil Strength

Abstract

A sound understanding of near-surface soil strength is essential for the accurate prediction of the response of structures laid on or shallowly embedded in the seabed. However, characterisation of the uppermost region of the seabed, which is typically very soft and at a low-stress state, is extremely challenging. This paper demonstrates a novel technique for characterising the in situ undrained shear strength of near-surface soils using a newly-developed pile penetrometer. The pile penetrometer is vertically embedded into the near-surface soil and is driven laterally. A simple calculation of the resistance mobilised over the embedded depth of the pile penetrometer is presented along with its application to the continuous measurement of spatial variation in near-surface strength in virgin and disturbed regions of soil.