###### Abstract
The research results of [PERSON] [4; 5] showed that the saturated interlayer water inside subgrade produces excess pore water pressure under the action of cyclic loading, which causes the vertical seepage of the water and the liquefied fine particles. [PERSON] [10] believed that the excess pore water pressure generated inside subgrade under cyclic loading drives the migration of fine particles, and the migration velocity of fine particles was analyzed. [PERSON], [PERSON], and other scholars [11; 12; 13; 14; 15] studied the influences of fine particles concentration and particles size on the characteristics of fine particles migration in porous media. [PERSON] [16] conducted an experimental study on the migration-deposition characteristics of suspended particles with different sizes in porous media, and divided the migration-deposition types of suspended particles into three types including filter cake filter type, migration-deposition type, and free movement type. On the other hand, the current researches on fluid-solid coupling characteristics have achieved rich research results. The coupling theory of water and soil (rock) was first used to solve the consolidation problem of soil. [PERSON] [17] studied the coupling phenomenon of fluid-solid deformation, and first proposed the concept of effective stress and established a one-dimensional consolidation model of soil. Subsequently, [PERSON] [18; 19] established a relatively complete three-dimensional consolidation theory. Since the establishment of [PERSON]'s three-dimensional consolidation theory, researchers have introduced different material constitutive relations and applied them to a wider range of fields. [PERSON] [20] considered nonlinear materials and proposed the generalized Biot formula on the basis of [PERSON]'s three-dimensional consolidation theory. In 1982, [PERSON] and [PERSON] [21] extended the [PERSON]'s three-dimensional consolidation theory to anisotropic elastic porous media. [PERSON] [22] introduced the dimensionless parameters to express the coupling effect of seepage and stress, and further extended the theoretical model of the coupling of multiphase saturated seepage in porous media. [PERSON] [23; 24; 25; 26; 27; 28] studied the effects of relative permeability, initial water saturation, residual oil saturation, and other factors on the interaction of multiphase fluid and solids through different new methods such as the volume of fluid (VOF) method, the coupled method of discrete element method (DEM) and volume of Fluid (VOF), and the coupled method of discrete element method (DEM) and computational fluid dynamics (CFD). These research results have important guiding significance for modeling the interactions between the particles and fluid in a multiphase fluid system. In 1977, [PERSON] [29] first combined [PERSON]'s consolidation theory with finite element method and applied it to slope stability analysis. [PERSON] [30] obtained a fluid-solid coupling model of piping failure based on the mass conservation equation and the continuity equation of seepage. [PERSON] [31] conducted artificial rainfall simulation tests on soil-rock mixture slopes, and studied the permeability of soil-rockmixture. On the basis of fluid mechanics and soil mechanics, [PERSON] [32] derived the equilibrium equation of porous media and the continuity equation of pore fluid considering the coupling of stress field and seepage field, and established a fluid-solid coupling model. However, the above researches on the characteristics of fine particles migration and fluid-solid coupling are mostly separate, and seldom involve the influence of fine particles migration on the hydraulic characteristics of coarse-grained soils. There is a lack of systematic research on the coupling effect between fine particles migration, fluid seepage, and deformation characteristics of solid skeleton.