Numerical research on two-dimensional bridge formation at the cohesionless sand-geotextile interface with the DEM method

Soil particles may be blocked at the pores of geotextiles even if the diameter of the soil particle is smaller than the size of the pores, and then a soil bridge is formed. To design a reasonable filter, it is vital to understand the formation of bridges at the soil-geotextile interface. The two-dimensional Distinct-Element Method was used to explore bridge formation at the cohesionless sand-geotextile interface. To realistically reflect the geological environment of cohesionless sand, the hydraulic gradient, confining pressure, multiple openings and inherent characteristics of cohesionless sand were covered in the simulations. It is found that both the number of openings of the filter and the uniformity coefficient of cohesionless sand had a substantial influence on the formation of a soil bridge. The bridge coefficient substantially decreased when there was more than one opening, because the narrower walls decreased the support of the bridge foot. When the confining pressure was greater than zero, the bridge coefficient was larger than that when there was no confining pressure. With the continual increase in the confining pressure, the confining pressure began to have an unfavourable effect on the formation of a soil bridge. The hydraulic gradient slightly decreased the bridge coefficient when the uniformity coefficient was 1.