Abstract
In order to examine the influence of void ratio on the collapse of the soil due to rainfall infiltration, suction unloading tests under anisotropic stress condition are implemented for specimens with different voild ratio. Not only loose specimens, but also dense specimens, with smaller void ratio than critical void ratio corresponding to specific suction, are compressed with suction unloading. If the initial void ratio is larger, the compression is also larger. The relationship between the reduction of void ratio and the increase of volumetric water content during suction unloading isn’t enfluenced by initial void ratio.