Investigation of a fluid–solid coupling model for a tailings dam with infiltration of suspended particles

Abstract

The study of the migration and deposition characteristics of suspended particles in porous media is significant in petroleum exploitation, groundwater recharge, filter design, nuclear waste disposal, and migration of underground pollutants. In recent years, researchers have tended to neglect the influence of tailings particle movement on seepage action in stability analysis of tailings dams. They have focused on analyzing the influence of tailings particle movement and deposition on tailings dams’ physical parameters. Based on the effective stress principle, the suspended-particle deposition equation is incorporated into the model of the fluid–solid coupling seepage field and combined with the stress field equation. Then, the particle deposition fluid–solid coupling model is established and gives the proper solution conditions for simplification. Based on a calculation program developed in-house, the stability of a tailings dam is analyzed while taking into account suspended particles. This approach aims to gradually reduce variation in percolation time growth of the coefficients of permeability and porosity. On this basis, we monitor the horizontal displacement and sedimentation values of the primary dam crest and of all levels of the sub-dam. We explore preliminarily the distribution law for tailings pore pressure to validate the correctness of the proposed mathematical model. Numerical analysis results show that in the process of deposition, the porosity, permeability coefficient, and flow rate become progressively smaller. The displacement of the primary dam is minimal and displacement of the third sub-dam is the largest, with displacement size displaying a relationship with dam height. The vertical displacement of the dam top gradually increases with increasing grades of sub-dams, and the difference is nearly 0.5 cm between the displacement of the primary and third dam crest-monitoring points. The results provide a theoretical basis for stability analysis of tailings dams undergoing tailings particle infiltration. Moreover, they provide reference material for studying migration and deposition characteristics of suspended particles in porous media.