EFFECT OF STRESS HISTORY AND SHALLOW EMBEDMENT ON CENTRIFUGE CONE PENETRATION TESTS IN SAND

摘要

The paper investigates the effect of stress history and shallow embedment on centrifuge cone penetration tests in sand. A series of centrifuge cone penetration tests were performed in loose and dense silica sand at g-levels ranging between 20 and 100 with corresponding overconsolidation ratio (OCR) between 1 and 5. Based on the measured cone tip resistance (q_c) profiles, improved empirical correlations have been proposed with depth factors (f_D) to impart additional flexibility in accurately back predicting sand relative density (R_D) at shallow embedment in normally consolidated (NC) sands. The q_c - R_D correlations are then extended to capture overconsolidation effects in cone tip resistance, which is broadly consistent with the changes in compressibility and in-situ lateral stresses taking place in sands with increasing OCR levels. The proposed expressions allow accurate quantification of depth corrected CPT profiles in soils of varying overconsolidation ratio, for application in the interpretation of model tests on shallow foundations and anchors and in shallowly buried structures such as pipelines. The expressions also have application for interpretation of field CPT profiles where the thickness of interbedded layers is of similar order of magnitude to the cone diameter.