Research on the construction of composite reverse filter using multi-graded gravel and stainless steel mesh

The core function of a tailings pond drainage system lies in effectively controlling the phreatic line of the dam and preventing seepage failure, while the performance of drainage and reverse filter materials directly determines the long-term stability of the system. Targeting the characteristics of fine-grained tailings, this study proposes a technical solution employing multi-graded gravel and stainless steel mesh to collaboratively construct a composite reverse filter （CRF）. Experimental results demonstrate that when utilizing continuously graded gravel （Cu=4.5, Cc=1.2） combined with 0.150 mm stainless steel mesh, the reverse filter system maintains a permeability coefficient ≥1×10⁻³ cm/s under sustained seepage, with a turbidity removal rate reaching 92%, showing significant improvement over single-layer filter systems. This research provides theoretical foundations and engineering references for the design of drainage systems in fine-grained tailings dams.