Characterizing the At-Rest Lateral Stress Coefficient in South Carolina Coastal Plain Quaternary Sands

This paper uses flat dilatometer and seismic cone tests at 10 sites and empirical relationships to characterize the at-rest lateral stress coefficient (K0) in the South Carolina Coastal Plain (SCCP) Quaternary sands. Plots of K0 and the dilatometer horizontal stress index (KD) generally exhibit increases with increasing age. Averaged K0 values range from over 4 near the ground surface to around 0.6 at a depth of 12 m. On the other hand, overconsolidation ratio (OCR), calculated using shear-wave velocity measurements, exhibits little dependency on age. Interestingly, for sites with and without liquefaction evidence, median K0, KD, and OCR profiles are similar below the groundwater table. The results provide new insights into the stress state of SCCP Quaternary sands and support the belief that lateral stress increases during secondary compression aging.