Experimental study on shakedown compression of saturated granular soils due to pore pressure variation

Field data revealed that compression in aquifer layers is the major source of ground subsidence and that compression of saturated granular soils due to fluctuations in pore pressure is important in this context. To investigate the mechanism of granular soil compression due to repeated pore pressure variations, a modified Rowe cell is developed to mimic the stress conditions in the field. The shakedown theorem is extended to saturated, granular soils under Ko condition. Remolded sand specimens with different mica contents are prepared to study the shakedown behaviors. Experimental results show that saturated granular soils under Ko condition will always be below the plastic shakedown limit, and shakedown responses are affected by the pore pressure amplitude, soil composition, and initial state. Comparisons of monotonic and shakedown compression reveal that the shakedown compression is at least as significant as the monotonic compression component, and clearly show that the shakedown effect should be included in ground subsidence analysis.