The deformation behaviour of an anisotropically consolidated kaolin clay under lateral cyclic loading

The soil behind wharfs or around pile foundations for wind turbines may be subjected to lateral cyclic loading. A series of cyclic triaxial tests were performed on a kaolin clay to study the response of the soil to lateral cyclic loading. Cyclic cell pressure was applied under a constant total vertical stress condition. The deformation behaviour of the clay under undrained condition is presented and discussed under different cyclic stress amplitudes, initial static deviatoric stresses and effective consolidation stresses. The results indicate that, the samples prepared under isotropic consolidation condition experienced axial extension, while those prepared under anisotropic consolidation condition exhibited axial compression under cyclic loading. There exists a static deviatoric stress ratio (between zero and 0.15) at which pure excess pore water pressure accumulates without axial strain development. Under anisotropic consolidation condition, with the increase of static deviatoric stress ratio, the deviatoric component of direction of strain accumulation increases in comparison to volumetric (excess pore water pressure) portion. The flow rule of Modified Cam Clay model (MCC) is revised to describe the direction of strain accumulation with the consideration of anisotropy of the clay. The predicted direction of strain accumulation is comparable with the observed values.