Analysis On The Influence Of Tailings Deposition Characteristics On The Stability Of Dam

The tailings pond is an important facility of the concentrating mill, and it is used for long-term storage of tailings, Which did not reach the technical and economic conditions of the useful components of mineral. The safety of the tailings pond is related to the safety of life and property of staff and downstream residents. It is also related to the normal development of mine production and living.Once the tailings pond had a failure accident, it will be a major disaster of mine production and living, it will result in casualties, economic losses and the serious pollution of the environment.From the time order, the subjective factors of affecting the safety of the tailings pond including site selection, engineering investigation, the design of tailings pond, construction, daily production operation and safety management. Each link is likely to cause the tailings pond accumulating irreversible hazards and defects.Due to the construction period of the tailings pond is the period of use, the period of use are generally more than a decade or even dozens of years, so the design of the tailings pond has irreplaceable long-term guiding significance for construction and operation of the tailings pond. The stability analysis of the tailings dam is an important part of designing the tailing pond. At present, at the time of designing the tailings pond model, the engineers did not consider the deposition features of tailings, or when they calculate the stability of the tailing dam, they use the physico-mechanical parameter of the full tailings, but in the process of the construction of the tailings pond, the tailings roll from millhole to the end of the tailings pond, due to the tailings’weight is different, the tailings deposit gradually from coarse to fine, the tailings dam structure will be affected by the deposition characteristics. So it is very important to research that how the tailings deposition characteristics influence on the tailings dam stability when we design it.I will study it from the two aspects.On the one hand,we will analysis that how the tailings deposition characteristics influence on the tailings dam stability calculation results; On the other hand, according to the inhomogeneity of sedimentary, calculate the reliability of the tailings dam stability and the sensitivity of the material. Through the analysis get the following conclusion:(1) In this paper a tailings is taking as an engineering example, we get the sample from the tailings export and along the direction of tailings flow. The sieve analysis method is adopted to sample particle analysis experiment. We can know the sedimentary characteristics of this tailings dam. In accordance with the "Tailings Spond Safety Technical Regulations"(AQ2006-2005) of appendix B, we can know all levels of the average particle size of tailings and divide the type of tailings in each position. For different categories of tailings do direct shear test and permeability test and get all kinds of tailings of shear strength, cohesion, coefficient of permeability.(2) For the first level of study, i will set up respectively two models of tailings pond.One is no deposit features, the other one is according to tailings deposition characteristics. Using the finite element method (fern) to analysis the tailings dam model of seepage respectively. Comparing seepage analysis results of the two kinds of tailings dam model under the condition of normal operation and flood operation. Results show the seepage stability of the sedimentary characteristics of tailings dam is better than no sedimentary characteristics.(3) Coupling the seepage analysis results to the dam stability analysis. By calculating the stability of the two kinds of tailings dam model. The model of considering the sedimentary characteristics’stability safety factor value of under the condition of normal operation and flood operation is smaller than the model that is regardless of the sedimentary characteristics.Under the special operating condition, we get the opposite result.So it is necessary in the preliminary design of the tailings spond considering the sedimentary characteristics of tailings. So the stability of tailings dam accords with the practice of it’s safety conditions.(4) On the basis of the first level, considering the inhomogeneity of tailings deposition, using monte-carlo method to analysis the reliability of the tailings dam stability under the condition of normal operation and flood operation and the special operating condition.The reliability index under normal operation conditions and flood operation conditions is greater than standard value(3.2) from "Water Resources and Hydropower Engineering Structure Reliability Design Standard "(GB 50199-2013) But the reliability index under the special operating condition is smaller than standard value.It is necessary to use reliability analysis method for dam stability calculation.(5) Combining with the reliability analysis results, analysising the sensitivity of the physical and mechanical parameters of all kinds of tailings material which influence the stability of tailings dam. The fine particle size of tailings’internal friction angle’sensitivity is the highest, under the three kinds of operating condition.That is the greatest influence on the stability of the tailing dam.