Model test study on electro-osmotic dry tailings dams of conductive grids

A significant amount of toxic substances and wastewater are stored in tailings dams. To lower their saturation line and reduce the risks of dam break and sewage leakage inside the dam, the traditional geogrid is combined with electrokinetic geosynthetics (EKGs) to generate conductive grids. Drainage tests on the tailings dam model were conducted using geogrids, EKGs, and a self-made conductive grid. The drainage effects, reinforcement effects, and electro-osmosis effects under static and electro-osmosis working conditions were compared and analyzed. The results show that the conductive grid exhibits the largest total water drainage, the strongest static drainage capacity, the smallest internal vertical pressure, the largest settlement, relatively small transverse cracks, and the lowest saturation line. Typically, the conductive grid is more energy-efficient. However, the value of its electrode contact resistance is larger than that of the EKG. This in turn results in a higher energyconsumption coefficient compared to EKG. During the electro-osmosis period of the conductive grid group, the water drainage is less than that of the EKG owing to the relatively large water drainage in the early static period, which increases the current resistance. After long-term electro-osmosis drainage, the rate of decrease of the parameters beneficial to electro-osmosis in the conductive grid is less than that of the EKG group. After approximately 10 h of the experiment, the electro-osmosis effect of the conductive grid exceeds that of the EKG, indicating that the conductive grid has better durability than the EKG. The conductive grid combines the advantages of the EKG and geogrid and exhibits good vertical and horizontal drainage capabilities, effectively improving the stability of the dam.