Study on filtration process of geotextile with LBM-DEM-DLVO coupling method

Abstract

The method of filtering and dewatering waste slurry using geotextiles has been widely used in recent years. It is important to adopt suitable geotextiles to get a high dewatering rate and a high retention performance. In view of the unclear influence of the geotextile properties on the cake and the unclear soil particle retention mechanism in geotextiles, this paper uses the Lattice Boltzmann method-Discrete Element method-DLVO (LBM-DEM-DLVO) coupling method to simulate the mesoscopic process of slurry filtration process using geotextiles. The numerical results show that the nature of the geotextile does not affect the hydraulic conductivity of the cake. And the retention mechanism for soil particles being trapped inside geotextile was proposed. The mechanism is related to the relative relationship between the interaction force between the geotextile fiber and the soil particle Finter and the drag force of the soil particle Fdy in the geotextile. The dimensionless ratio αsl=Finter/(Fdy+G) was proposed to quantify this retention mechanism; the smaller αsl is, the greater the probability that the geotextile will lose particles. When αsl ≥ 1.04, the geotextile does not lose particles. According to these results, some suggestions of geotextiles for dewatering slurry were proposed.