Elasto-plastic deformation of hostun sand during cyclic loading in triaxial test

Abstract

Cyclic triaxial tests were performed on dry air-pluviated solid cylindrical (7 cm diameter and 15 cm high) specimens of Hostun sand (French sand). Both axial and radial strains were measured locally by using, respectively, a pair of Local Deformation Transducers (LDTs) and three pairs of gap sensors. An isotropically consolidated specimen (at 78.4 kPa) was subjected to cyclic prestraining (CP) with a large number of relatively large amplitude axial-stress cycles. Elastic Young’s modulus Ee defined for an axial strain increment less than 0.002% was evaluated at various stress-states along the CP stress path. The effects of CP were investigated on elastic and plastic deformation characteristics along the CP stress path. Elastic parameters were changed slightly due to CP although the overall elastic deformations along the CP stress path were more stable than the plastic deformation characteristics. The plastic deformation component was drastically affected by CP. As a result, the stress-dilatancy relation was changed in a complicated manner.