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

Abstract

In this study, a relationship between small-strain shear modulus (Gmax) and overconsolidation ratio (OCR) based on shear wave velocity (VS) 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 VS 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 VS measurements irrespective of normally-consolidated or overconsolidated loading conditions. Finally, the developed Gmax-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.