Mesoscopic numerical tests on seepage failure characteristics of coarse grained soils

To deeply explore the influences of seepage failure on permeability feature of coarse grained soils, based on the analysis of indoor experiment results of seepage failure tests on coarse grained soil samples, the software named PFC^3D is employed to simulate the whole process of seepage failure with similar test situation. The research results show that the fine particles in the samples migrate from“upstream” to “downstream” location with the increment of water head. The fine particles are gathered at the downstream location of the seepage path in the test samples and the compaction area is formed due to seepage. The phenomenon of seepage compaction induces the decrease of permeability of the test samples. Under the action of the increasing water head, the fine particles in the compaction area migrate out of the samples with seepage water. The coefficient of permeability also increases gradually. The porosity of the test samples becomes large due to the loss of the fine particles. The skeleton structure of the soil test samples is also changed. This is the reason for the increase of permeability of the coarse grained soils due to seepage. When a larger mount of the particles are brought out of the soil samples, the phenomenon of seepage failure is then formed. It is also indicated that the mesoscopic numerical test method can recreate the process of seepage failure reasonably.