Relationship Between Undrained Shear Strength and Shear Wave Velocity for Clays

The interrelationship between undrained shear strength (s(u)) and downhole shear wave velocity (V-sVH) of normally consolidated (NC) and lightly overconsolidated (LOC: OCR < 2) to overconsolidated (OC) to highly overconsolidated (HOC: OCR > 10) clays is investigated in the presented study. The main objective of this research program is to develop a worldwide database of high quality in-situ geophysical and laboratory strength data from thirty seven well-documented geotechnical sites from locations in Australia, Brazil, Canada, China, Italy, Japan, South Korea, North Sea, Norway, Singapore, Sweden, Thailand, United Kingdom, USA, and Vietnam. The study includes undrained shear strength measurements on undisturbed samples of normally to lightly overconsolidated intact to overconsolidated and fissured clays using anisotropically-consolidated triaxial compression tests (CAUC). Shear wave velocities were measured in the field by downhole tests (DHT), in many cases via seismic piezocones (SCPTu). Analyses of the compiled database found approximate trends between undrained shear strength and shear wave velocity. Tentative correlations are explored by including other various parameters such as Atterberg limits, void ratio, overconsolidation ratio (OCR), and effective vertical stresses. The correlative trends may aid geotechnical engineers in helping to assess s(u) profiles in clay deposits in preliminary investigations and as an independent method in collaboration with sampling, lab testing, and other field data.