OCR evaluation of cohesionless soil in centrifuge model using shear wave velocity

Abstract

In this study, a relationship between small-strain shear modulus (G(max)) and overconsolidation ratio (OCR) based on shear wave velocity (V-S) measurement was established to identify the stress history of centrifuge model ground. A centrifuge test was conducted in various centrifugal acceleration levels including loading and unloading sequences to cause various stress histories on centrifuge model ground. The V-S and vertical effective stress were measured at each level of acceleration. Then, a sensitivity analysis was conducted using testing data to ensure the suitability of OCR function for the tested cohesionless soils and found that OCR can be estimated based on V-S measurements irrespective of normally-consolidated or overconsolidated loading conditions. Finally, the developed G(max)-OCR relationship was applied to centrifuge models constructed and tested under various induced stress-history conditions. Through a series of tests, it was concluded that the induced stress history on centrifuge model by compaction, g-level variation, and past overburden load can be analysed quantitatively, and it is convinced that the OCR evaluation technique will contribute to better interpret the centrifuge test results.