A METHOD FOR EVALUATING VOLUMETRIC STRAIN RESULTING FROM LIQUEFACTION OF SANDY SOIL BASED ON CYCLIC SHEAR STRAIN HISTORY

Abstract

 The objective of this study was to investigate the effects of fine fraction content, initial specimen density and residual shear strain after undrained cyclic shear in regard to the reconsolidation behavior of sandy soil at the post-cyclic shear stage. To this end, multiple stress-controlled cyclic shear torsional tests were conducted in undrained conditions. The results revealed that volumetric strain after sandy soil liquefaction is dependent on the history of shear strain hysteresis during cyclic shear regardless of the fine fraction content of the specimen. Higher values of volumetric strain at the postliquefaction stage corresponded to higher values of cyclic shear strain history. Conversely, lower values of volumetric strain at the post-liquefaction stage corresponded to higher values of initial relative density. Furthermore, when residual shear strain was seen after cyclic shear, lower values of volumetric strain corresponded to higher values of residual shear strain. These results indicated that the history of shear strain hysteresis during cyclic shear is an effective index for evaluating volumetric strain at the post-liquefaction stage. In this study, model tests using a shaking table were also performed to verify the results of the element tests. The outcomes showed that the above-mentioned index is suitable not only for use in elementary tests but also for use in shaking table tests to evaluate reconsolidation volumetric strain.