Experimental Study On Permeability Characteristics Of Tailings Based On Stability Of Uranium Tailings Pond

In order to analyze the influence of the permeability characteristics of uranium tailings on the stability of uranium tailings pond,the regional survey and research status of a uranium tailings pond in southern China were summarized through field survey and related geological literature.The basic physical parameters,soil water characteristic curve,permeability and permeability coefficient of uranium tailings sand were measured and studied.Finally,the measured data and parameters are combined with GEO-studio simulation software to analyze and summarize the seepage and stability of the uranium tailings reservoir under normal and flood conditions.The results show:(1)The matric suction of the three tailings determined by the filter paper method decreased with the increase of water content,and both showed a change rate of rapid change rate when the water content was low.The water holding capacity of the three uranium tailings is gradually increasing with the increase of the average particle radius.The soil-water characteristic curve fitted by the Van Genuchten model has strong correlation and good fitting effect.(2)The results of non-steady-state liquid flooding permeability test show that under the action of the inlet pressure,the permeability of the three tailings decreases with the trend of time,and the water output increases gradually and has no downward trend.The influent pressure rises first and then stabilizes during the change of permeability.(3)The results of unsteady gas-liquid relative permeability test show that the change of permeability of tail sand and tail fine sand is not completely the same with time.Nitrogen has small permeability due to pore channel in tailings with smaller average particle radius.The rate is low and difficult to pass.It can be seen from the fitting curve of the relationship between matrix suction and permeability coefficient that the permeability coefficient of different tailings decreases nonlinearly with the increase of matrix suction.(4)The numerical simulation results of a uranium tailings reservoir by GEO-studio software show that the permeability coefficient of the saturated tail sand is obviously larger than that of the tail fine sand.The water flow under normal and flood conditions mainly flows from the saturated tail sand layer,and the water flow mainly Converging at the location of the tailings dam near the initial dam,as the operating conditions intensify,the hydraulic gradient inside the dam is getting larger and larger.The deeper the slipping noodle block,the greater the shear strength,the greater the hydraulic gradient,and the greater the pore water pressure.In the calculation of normal and flood conditions,the safety factors are 2.038 and 1.920 respectively,which meets the requirements of the regulations and the dam is relatively stable.