Research On Risk Assessment Model And Control Strategy For Tailings Dam Failure

With the development of mining in our country,there are a lot of tailings dams.The number of tailings dam is the largest in the world.Tailings dam is a major hazard source that may cause debris flow and other hazards,and the dam break accident will cause great damage and threat to the surrounding environment and residents' lives and property.It is necessary to strengthen study on the risk management of tailings dam.In this paper,the extension matter element theory and system dynamics theory will be adopted to evaluate the tailings dam break risk based on the life cycle perspective,and analyse the evolution law of dam break risk in different stages.Based on the previous research,the corresponding countermeasures are put forward.(?)Based on the whole life cycle theory,the risk index system of tailings dam break is constructed.Through collecting the typical dam break accident cases,the causes of these accidents are analyzed from each stage of the life cycle of the tailing pond,and the characteristics of tailings dam break risk are summarized.This paper expounds the concrete contents of each stage of the whole life cycle of tailing pond,and analyzes the characteristics of life in every stage of tailing pond.On this basis,from the three stages of the survey and design,construction and operation,the risk factors of tailings dam break have been identificated and analysed,the assessment index system of tailings risk has been created.The index system includes 3 first level indicators,9 second level indicators,46 third level indicators,and using the analytic hierarchy process to obtain the specific weight value of each index.(?)On the basis of comparative analysis of the risk assessment model and method,the matter element model was selected to evaluate the of dam failure risk.Based on the tailings dam risk index system and weights built earlier,using the matter element method to obtain the correlation matrix of the risk factors and the risk grade of the tailings dam break,by calculating the correlation degree between the measured value and the actual risk grade to obtain the comprehensive risk grade of the tailings dam break risk.In this paper,taking the whole life cycle of a tailings dam as an example,the risk assessment of tailings dam break is developed.The results show that the dam break risk level of the tailings dam is the first class of risk,that is,the risk of the entire life cycle has been at a low risk level.The risk level of the survey and design phase is at the second stage risk level,construction stage for the first level of risk,operation stage is at second stage,the overall risk level of each stage is low.(III)The risk of tailings dam break is analyzed based on the system dynamics,The characteristics of system dynamic of the tailings dam break are summarized,and the purpose of modeling is clear and definite,and the feedback effect and delay effect of tailings are expounded.Further,based on the modeling methods and ideas of the system dynamics,the system dynamic model of tailings dam break risk is established.The causal analysis and static analysis of the model are carried out.(IV)In this paper,the risk evolution of tailings dam break is studied by three aspects.On the first aspect,the dynamic evolution law of tailings reservoir at various stages and the risk of dam break.System simulation shows that,for a case of the maximum value of the overall risk is certain;the risk of tailings dam break with the passage of time generally presents the trend of wave type.However,there is a difference in risk evolution in the different stages of the life cycle of tailing pond.Survey and design stage,as the beginning stage of the life cycle of tailing pond,no other risk stage impact it,dam break risk appears to be "S" type growth,the risk rate is parabolic type.In the construction stage,the risk of dam break appears step type growth and still increases.There are two peaks in the risk rate of dam break at this stage,and this is due to the risk coming from the survey and design phase,which make the risk transfer,On the basis of risk in the construction stage,coupled with the risk of the previous stage.At the operation stage,the total risk of dam break is further increased,showing a wave of rising,the amount of risk to reach the maximum value,It shows that the probability of dam break accident of tailings dam has reached the maximum value.Duing to the cumulative effect of risk factors and the control action,the increase rate of total risk reduce but the total risk quantity of dam break presents an upward trend.The second aspects is the impact of enterprise risk early warning value on tailings dam break risk,the simulation results show that the size of the risk early warning value has a significant impact on the risk of dam failure.The third aspect is the impact of enterprise risk investment on tailings dam break risk,the simulation results show that the risk investment increases in the survey design stage helps to better prevent and control the risk of tailings dam break.(V)According to the risk evolution trend and the main risk factors of the dam break,from the survey design,construction and operation stage,put forward the corresponding countermeasures.Provide support for the control of the risk of dam break in the tailings dam.