Effects of Accumulation Depth and Dry Density on Oil and Water Characteristics of Unsaturated Tailings
The tailings sand stored in the tailings reservoir of metal and non-metal mines is mostly in the unsaturated state after free settlement.Therefore,in order to study the changes of soil and water characteristics of unsaturated tailings under the influence of different accumulation depths and dry density,a pressure plate instrument was used to carry out unsaturated soil permeability test on tailings sand samples from a molybdenum mine in Heilongjiang province.The results show that with the increase of deposit depth,the water content and permeability coefficient of tailing sand increase.When the matric suction is 80 kPa,it is the characteristic point of soil and water characteris-tic curve change of shallow and middle tailing sand,while deep tailing sand has no obvious characteristic point.For the samples with higher dry density,the characteristic curve of water and soil is relatively smooth and the slope is small.When the matric suction is greater than 350 kPa,the water content tends to be stable.The increase of water content of tailing sand with shallow accumulation depth and small dry density leads to the sudden drop of matrix suction,which is easy to cause the safety problem of tailing reservoir.The research conclusion has important refer-ence significance for improving the process of tailings drawing and dam construction and increasing the stability co-efficient.
unsaturated tailingsaccumulation depthdry densitysoil and water characteristic curvepermeabili-ty coefficient