Analysis Of Instability And Collapse Process Of Tailings Dam And Simulation Of Dam-break Debris Flow Disaster

With the rapid improvement of global industrialization,human demand for ore resources is increasing.However,in mining development activities,people not only obtain valuable mineral products,but also produce a large amount of waste residue(tailings).To prevent environmental pollution,these waste residues are discarded in the tailings pond,which also makes the tailings pond a necessary production facility for metal and non-metal mines.With the increase of the mining speed of mineral resources and the development of beneficiation technology,more and more tailings are discharged,the number of tailings ponds and the stacking height of tailings dams are increasing,and the risk of dam break due to the instability and damage of tailings ponds is also increasing.In recent years,dam break accidents of tailings pond caused by different factors have occurred from time to time,which has caused huge losses to the life and property of residents in the downstream of the reservoir area and the surrounding environment.How to effectively reduce the loss caused by tailings dam break,especially the injury to personnel,has always been paid attention to by the competent government departments and mining enterprises.The former State Administration of work safety specially stipulated in the document "ajzg-(2016)No.49" that "the tailings pond with the height of the accumulation dam exceeding 10 m should be subject to dam break numerical simulation or model test to determine the impact on the downstream after dam break".From the perspective of intrinsic safety,it put forward specific requirements for the safety production management of tailings pond and the prevention and control of dam break disaster.Therefore,taking Yuzuzha tailings pond of Yunnan Chuxiong mining and Metallurgy Co.,Ltd.as the engineering background,this paper makes an in-depth and systematic study on the deformation instability and collapse process of the tailings dam,the evolution process and burial range of dam-break debris flow by using the comprehensive research methods of theoretical analysis,numerical simulation and physical model test.It is conducive to fully understand the characteristics of dam break disaster of tailings pond and guide the disaster prevention and control work in the downstream of the reservoir area.The main work and achievements of this paper are as follows:(1)The engineering characteristics of Yuzuzha tailings pond of Yunnan Chuxiong mining and Metallurgy Co.,Ltd.and the surrounding environment downstream of the reservoir area are collected and analyzed.According to the field investigation report,the basic data such as particle composition and physical and mechanical properties of the deposited tailings in the reservoir are obtained;Through the indoor fluid viscosity test and the empirical formulas for calculating the yield stress of debris flow,the rheological characteristics of tailings slurry are obtained,which provides a basis for the next analysis of the instability and collapse of tailings dam and the debris flow disaster of dam break.(2)Using Seep/W module,Sigma/W module and Quake/W module of Geo-Studio software,the seepage field and stress field of Yuzuzha tailings pond accumulation dam are analyzed,and the variation laws of seepage field,pore water pressure,shear stress,displacement and deformation instability process of tailings dam under flood and earthquake conditions are obtained.(3)Based on the indoor physical model test,the collapse process and failure form of Yuzuzha tailings dam under flood condition are studied,and the variation characteristics of dam internal displacement and the development law of breach are obtained;Based on the Slope/W module analysis of Geo-Studio software,the position of potential sliding surface and slide wedge range of tailings dam under flood and earthquake conditions are obtained.Combined with the empirical formulas of reservoir dam break,the total discharge volume,breach size and discharge hydrograph at the breach under the two conditions are calculated.(4)Based on the digital terrain model of Yuzuzha tailings pond and its surrounding areas,the evolution process of dam-break debris flow under flood and earthquake conditions are simulated by using FLO-2D software,and the movement route,flow depth,flow velocity and their variation law of dam-break debris flow under the two conditions are obtained;At the same time,the effects of total discharge,pulp concentration,surface vegetation and retaining works on the disaster situation in the downstream after dam break are analyzed,and the corresponding disaster prevention and reduction measures are put forward.