Three Dimensional Seepage Stability Analysis Of Tailings Dam And Optimization Of Layout Mode Of Drainage Facilities

Tailings pond is an important place for storing tailings and water,and it is also a huge hazard source.If the tailings dam breaks,a large amount of mineral sand mixture stored in the reservoir will pour down,which will serious threat to life and property safety and environment in downstream areas.Among the many factors affecting the stability of tailings dam,seepage is the main reason for the collapse of tailings dam.Therefore,the study on seepage stability analysis of tailings dam is a very important and practical topic.Taking an upstream tailings pond in Heilongjiang Province as the research object,on the basis of obtaining relevant engineering data,considering engineering geological conditions of tailings pond,this paper establishes the three-dimensional seepage numerical model of tailings pond through MIDAS-GTS NX large-scale finite element analysis software.This paper analyzes the changes of seepage field in tailings dam under different dam height and water level conditions,focuses on the impact of seepage drainage facilities such as geomat,seepage drainage wall and horizontal seepage drainage pipe on the seepage field of tailings dam,optimizes the layout of seepage drainage facilities,and finally,the strength reduction method is used to analyze the static stability of the tailings dam slope.The main contents of this paper are as follows:1.This paper summarizes the harm caused by tailings dam break accident at home and abroad,the causes of dam break accident and the research status of seepage in tailings dam,and mainly introduces the engineering characteristics and principles of several seepage drainage facilities in tailings dam and the engineering situation of LM tailings pond.2.Based on MIDAS-GTS NX finite element software,the three-dimensional seepage model of tailings pond is established,the distribution of water head and infiltration line of tailings dam under different working conditions of current dam height are analyzed,and compared with the measured infiltration line of tailings dam.The results show that the three-dimensional seepage simulation results are in good agreement with the measured values,and this model can be used in the subsequent analysis.The seepage control effect of three kinds of seepage control facilities is compared and analyzed.It is found that the seepage control effect of geomat is the best.3.The seepage field after the heightening and capacity expansion of the tailings dam is analyzed.When the dam height is 100 m,the infiltration line overflows from the downstream dam slope of the accumulation dam,which does not meet the safety design requirements specified in the specification,and seepage control treatment is required.Based on the beneficial conclusions of the third chapter,the optimal layout of the geomat is carried out,and the seepage control effects of the geomat under different layouts are compared and analyzed.The results show that the layout scheme of the geomat with 6m width and 6m vertical spacing is the optimal seepage control scheme.4.Based on the strength reduction method,the static stability of tailings dam slope is analyzed.Through comparing the condition of tailings dam under the limit state of displacement and the minimum safety factor is calculated,the relationship between dam height and water level is summarized.The conclusions are drawn,with the continuous heightening of tailings dam,the safety factor of slope stability decreases,while the contribution ratio of seepage drainage facilities is increasing.When the optimized geotechnical cushion works normally,its seepage control function can increase the safety factor of slope stability of tailings dam by 20%-70%,which provides a certain reference basis for the design and construction of tailings dam.