| Tailings pond is used to accumulate tailings,which has the characteristics of high potential energy and high pollution.As the waste of concentrator,tailings contain valuable components that cannot be treated under limited conditions or harmful components that may cause heavy metal pollution to the natural environment.Once the dam breaks,there will be a large number of tailings discharge,which will not only cause resource loss and environmental pollution,but also bring serious impact on downstream residents,houses,farmland,roads and Bridges and other facilities,resulting in casualties,property losses and long-term irreversible pollution to the natural environment.Although the number of tailings ponds in China has been declining for 12 consecutive years since 2007,by the beginning of 2020,the total amount of tailings ponds in China still ranks the first in the world,with nearly 8,000.Among them,the number of "overhead storage" has 1,112,involving more than 400,000 downstream residents.Therefore,through relevant data,computational fluid dynamics is used to simulate the evolution law of sand flow and protective measures after tailings pond dam break,so as to make more targeted plans,which is of great significance to the disaster prevention and mitigation of tailings pond.Based on computational fluid software tailings in a project are the three dimensional numerical simulation of the condition and terminal conditions to explore the present situation of tailings dam,the evolution of distance impact,the effects of parameters such as speed and submerged depth,and according to the results of the simulation analysis of fluid to the downstream tailings dam dam important facilities such as railway,houses submerged depth influence degree.In order to reduce the impact of dam break sand flow on the downstream area,the protective measures model is established and the evaluation effect of engineering measures is obtained.The thesis mainly does the following work:(1)Simulate and verify the dam break model in computational fluid software based on the overtopping dam break test in literature.The results show that the morphological changes of the simulated guided fracture are roughly consistent with those of the experiments in the literature,and the variation trend of the simulated data is the same as that of the experimental data,which verifies the feasibility of the physical model.(2)After the occurrence of tailings pond dam break,the dam break fluid evolved downstream.With the increase of the distance from the dam foot,the flow showed a decreasing trend,and the maximum average velocity of each section showed a decreasing trend on the whole,but a few sections located at the rear were larger than the front section due to topographic fluctuations.The dam break fluid initially reached the main residential area under the current working condition,and half of the main residential area was flooded under the final working condition.(3)For the first working condition,two protective measures of two modes are set up at 50 m and 50 m and 100 m respectively.After the engineering measures are taken,the maximum average velocity of the front end decreases along the flow evolution direction,and the flow of each section shows a decreasing trend on the whole.(4)For the second working condition,a grid type retaining dam is adopted to reduce the maximum average velocity of the front-end along the direction of flow evolution,while the maximum flow rate of the section increases,which has a more obvious protective effect on railway Bridges. |
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