Experimental Study On The Characteristics Of Fissures And Radon Exhalation On The Beach Surface Of Uranium Tailings Pond Under Low-Frequency Dynamic Loads

Earthquake is one of the disadvantageous factors of uranium tailings.According to China Earthquake classification map and relevant data,there have been earthquakes with magnitude above 7 in the area of uranium tailings pond.In addition,we need to consider other extreme conditions when the earthquake occurs,especially in the case of superposition of various natural hazards,the stability of uranium tailings pond is affected.When real earthquakes occur,most of them show the characteristics of random dynamic load,which can be simplified as lowfrequency dynamic loads for the convenience of research.However,the uranium tailing pond is sensitive to vibration.Under the condition of lowfrequency dynamic loads,the beach surface of the uranium tailing pond will be damaged and fissures will be produced,resulting in the overall destruction of the overburden.The mechanical structure of overburden is unstable,which makes the radioactive radon in the beach of uranium tailings pond accelerate,which affects the surrounding people and environment.In order to study the characteristics of fissures and radon exhalation on the beach surface of uranium tailings pond under lowfrequency dynamic loads,the measures to prevent and control radon on the beach surface are optimized.Based on the similarity theory,a model of uranium tailing pond beach surface with similar geometry,physics and initial condition was made in this paper.According to the scale model,the experimental study on the fissures and radon exhalation of the beach surface of uranium tailings pond under low-frequency dynamic loads was carried out by using the orthogonal design method and the self-developed shaking table test device,and the damage of the beach surface during vibration was reproduced.The whole field deformation measurement and simulation optimization analysis system(Match ID)was used to analyze the generation and development process of fissures on the beach surface of uranium tailings pond under low-frequency dynamic loads,and the relationship between the fissures and radon exhalation characteristics is obtained,which provides some reference for the prevention and control of radon on the beach surface of uranium tailings pond under actual lowfrequency dynamic loads.The main contents of this paper are as follows:(1)Self-made shaking table test device.In order to study the fissures development and radon exhalation characteristics of the beach surface of uranium tailings pond under low-frequency dynamic loads,a self-made shaking table was designed to simulate the effect of lowfrequency dynamic loads.(2)Measurement of test parameters,design and manufacture of beach surface model of uranium tailings pond.The physicochemical and radioactive parameters of uranium tailings were measured by means of infrared spectroscopy,XRF and screening tests.And according to the similarity theory,the beach model of uranium tailing pond meeting the test conditions was made.(3)Study on the development of fissures on the beach surface of uranium tailings pond under low-frequency dynamic loads.The whole field deformation measurement and simulation optimization analysis system(Match ID)was used to detect the beach surface damage and defects of uranium tailings pond.(4)Study on radon exhalation rate of uranium tailings pond under low-frequency dynamic loads.The scale model of the beach surface of uranium tailings pond was placed on a small shaking table,and the lowfrequency dynamic loads with different frequencies and loading time were applied to it.Then the radon concentration was measured by Rad-7 radon meter,and the radon exhalation rate was further calculated by combining with the relevant formula.(5)The study on the characteristics of the damage and radon exhalation in the beach of uranium tailings pond under low-frequency dynamic loads.The influence of vibration frequency and loading time on the damage of the beach surface and radon exhalation in uranium tailings pond was considered.The model of beach surface resonates with the frequency of 24 Hz,which had strong damage to the structure of the beach,and the fissures were fully developed and the number increased.The surface fissures increased the gas channels where radon could diffuse and convection,and the radon exhalation rate increased.