Experimental study of suffusion characteristics within granite residual soil controlling inflow velocity

Suffusion is a particular case of internal erosion due to water seepage through a porous media, which is a main cause of the failure of dam and embankment. There are a lot more to understand due to its inherent complexity. In order to study the development of suffusion, a test device taken into account inflow velocity is designed to simulate the suffusion process in this paper. Three laboratory tests on granite residual soil are presented aimed at investigating the suffusion erosion of fine particles from soil samples subjected to a controlled inflow velocity. The processes of erosion can be observed during the tests. The variation of wetting front, moisture, and erosion amount under different inflow velocities is measured to study the effect of inflow velocity on suffusion within granite residual soil which has high contents of fine particles. As the inflow velocity increases, the wetting speed of the wetting front will increase, and the erosion amount will also increase. The larger inflow velocity would lead to the higher extent of suffusion. The soil column will form preferential channels or fine particle redeposition, which will cause the soil moisture content to fluctuate. The suffusion process in granite residual soil includes fine particles erosion, reposition, pore clogging, and flushing.