Experimental Study on the Migration and Clogging of Fine Particles in Coarse-Grained Soil with Seepage

Abstract

The migration and clogging of fine particles in the pores of coarse-grained soil with seepage is of great significance to reduce the leakage of soil at the dam base and lower the permeability of soil. Therefore, the homemade infiltration test device was used to test the infiltration and clogging of soil samples with different particle size ratios D15/d85 (D15 represents the particle size corresponding to the cumulative percentage content of soil particles smaller than a certain particle size in the coarse particles which is 15%, and d85 represents the particle size corresponding to the cumulative percentage content of soil particles smaller than a certain particle size in the fine particles group which is 85%). The factors affecting the deposition of fine particles in coarse-grained soil and the characteristics of fine particle migration and penetration were analyzed. The clogging of coarse-grained soil, hydraulic gradient and pore changes characteristics before and after clogging were studied. The results show that: 1) The main factor affecting the retention of fine particles in coarse-grained soil is the particle size ratio, and the retention rules conforms to the Peak-Gauss function relationship. The penetration law of fine particles satisfies the Logistic function relationship, which can directly predict the internal clogging of coarse-grained soil. 2) The particle size ratio is the main factor affecting the blockage in each mode, followed by the influence of the water head, When the particle size ratio is less than 13.10, the clogging ratio decreases with the increase of particle size ratio, and the hydraulic gradient increases with the increase of particle size ratio. When is greater than 13.10, the clogging ratio increases with the increase of particle size ratio, and the hydraulic gradient decreases with the increase of particle size ratio. 3) The degree of clogging in coarsegrained soil is closely related to the change in porosityand and can be judged according to the change of porosity in coarse-grained soil. The research results deepen the understanding of fine particle migration on the rules of coarse-grained soil clogging and can provide a theoretical basis for related engineering applications.