

High precision triaxial tests are described on loose silica Thames Valley Sand (TVS) that explore interactions between K0 compression, creep under a constant anisotropic stress regime and low-level, drained, deviatoric load cycling. The experiments reveal approximately semi-logarithmic creep time trends after K0 loading that show well defined ‘time origins’ and gradients that steepen with stress level. However, marked rotations of the creep strain increment directions are noted with time with dεvol/dεs falling from 3/2 to negative (dilative) values. Such changes can be restrained by increasing the consolidation stresses. The strain increment vector re-orientation is understood in terms of a framework of nested kinematic yield surfaces that can be extended and hardened by creep and low level cyclic loading. Log-linear strain-time (or cyclic number) trends are seen under cyclic loading, whose gradients steepen with cyclic amplitude qcyclic. Creep stages imposed before cyclic loading reduce markedly the subsequent cyclic strain accumulation rates. When cyclic straining processes are isolated from background creep rates, they tend (under the levels imposed) to stabilize after several thousand cycles. The phenomena observed have significant implications for settlement prediction with foundations that experience significant environmental loading as well as those that undergo regular loading service cycles. The evolution with time of permanent strain development patterns may also prove helpful in understanding otherwise unexpected trends, such as the ageing trends of piles driven in sand.