| The tailings sand in tailings dams has the property of strong water absorption,which is susceptible to rainfall leading to tailings dam failure.In this paper,a tailings dam in Miyun district of Beijing is used as the research background,and the combination of 3D modeling,model tests and numerical simulations is used to focus on the study of the change law of the stability state of the tailings pond and its damage process under heavy rainfall conditions,and the stability indexes of the tailings pond under heavy rainfall conditions are calculated and evaluated based on the hierarchical analysis method,and the main research results are as follows:(1)The stratigraphic data obtained from the known exploration report was refined to stratify it,and the density related index of infiltration was selected as the reference basis,and classified into softer and harder layers based on the results of the calibration test,and the internal structure of the soil layer could be seen more intuitively after relying on Arc GIS to realize 3D modeling,and the ideal cross-section was intercepted through Arc Sence to provide reliable cross-section for the numerical simulation later on.(2)Through the simulation of a tailing pond in Miyun under four kinds of rainfall conditions,seepage analysis,displacement field analysis and slope stability analysis,the stability state change law of the tailing pond under different rainfall intensity conditions was obtained.The research results obtained: in the early rainfall,the greater the rainfall intensity the worse the stability of the tailings pond;when the rainfall amount is the same,the stability of the relatively small rainfall intensity is worse;when the rainfall intensity is the same,intermittent rainfall is less stable than continuous rainfall;when the rainfall intensity to higher intensity,the final stability coefficient does not change much;long time rainfall is fully penetrated into the interior of the tailings dam,the dam is more likely to occur deep damage;In the strong rainfall conditions tailings dam stability,mainly affected by the infiltration time.(3)completed the tailings pond dam-break test under strong rainfall conditions,summarized the law of water content,infiltration line,pore soil pressure and other related factors in the whole dam-break process in different locations of the tailings pond during the rainfall process,and obtained the law of the influence of related factors on the stability of tailings pond under strong rainfall through the comparison of two tests.The test results show that: the tailings sand still maintains a high water content after the dam break,and the tailings sand will not lose water immediately after the dam break,so there is a potential risk of secondary dam break;the infiltration line continues to work at a high water level before the dam break occurs,and decreases rapidly after the dam break occurs,which indicates that the possibility of dam break is higher in a long time high water operation reservoir;when the intensity of rainfall is very heavy and intermittent,it is more threatening to the stability of the tailings reservoir compared with continuous rainfall.When the rainfall intensity is very heavy and intermittent,the threat to the stability of the tailings pond is greater than continuous rainfall.(4)Dam structure,soil index,and daily management were selected as indicators of tailings dam failure risk under rainfall conditions,and the final weights of each factor were obtained based on the hierarchical analysis method by assigning weights to the factors through expert scoring and previous studies to assess the risk of tailings dam failure under rainfall conditions.The stability of the tailings pond under rainfall conditions is very important,especially the slope ratio of the tailings pond,and the stability of the same tailings pond under different slope ratios with rainfall conditions in the background.After the tailings pond is closed,human management is also an important indicator. |
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