The Mechanical Behavior Of Tailings Macro-micro Affected By Pore Water And The Stability Analysis Of Tailings Dam

The rapid development of modern industrial technology, not only to meet thegrowing needs of daily life, but also accelerate the development and utilization ofmineral resources, which brings convenience to people’s lives, as well as brings moreabandoned slag tailings. Tailings usually discharged in the form of slurry and pilling intailings reservoir, which is a particular soil-water coexistence structures, one of the threecontrol projects in mine, its stability not only determines the economic benefits ofmining enterprises, but also affects the life and property safety of downstream residents.Tailings reservoir is not uncommon in recent years, every outbreak of the accident,natural or manmade reason, which brought huge impact to the community. Therefor thestability study of tailings reservoir become more and more important, the developmentof modern science and technology as well as computer applications, make the tailingsdam stability prediction and research effective, and have had some correspondingresults. However, the transmutation of microscopic particles leaded to the macroinstability and failure of tailings dam. Based on this theory mechanism, the paperresearched the strength characteristics of tailings particles in different moisture and thetailings dam seepage field impacted by the rainfall, as well as the stability analysis oftailings dam at different conditions by room soil test, tailings dam experiment andcomputer numerical simulation. The main research results are follows:①Based on the Yunnan Dahongshan copper tailings research, the results showsthat the shear specimen peak increased slightly with the increasing of water content andthe moisture content fluctuation12%-18%, which was affected by the differentconfining pressure. While the moisture content exceeded the liquid of20.5%, the shearspecimen peak was lower than18%. The cohesion increased with water content at first,and then decreased while the water content beyond17%. Based on the above research,the optimum moisture content is17%-18%and the water content has little effect on theinternal friction angle.②The subsidence displacement curve of tailings material which was in differentmoisture content and affected the continuous load as well as microscopic deformationevolution mechanism was analyzed in the paper. When the moisture content was near orbelow the liquid limit, the load growth curve was divided into four stages with theincrease of subsidence displacement. They were linear growth, drastic mutation, stable and significant growth respectively. After linear growth phase, the tailings particlesexperienced1.4mm subsidence displacement and the small particles would beintegrated into the pores between the large particles and the block structures whichmade the particles contact closely and the structure more stable.③The seepage of the tailings dam and the anti-sliding stability coefficient wereresearched with the application of GEO software in the paper. The negative pore waterpressure gradually decreased and the saturation line went up a litter in rainfall. Theanti-sliding stability coefficient of tailings dam was different with the rainfall types.When the rainfall increased gradually, the anti-sliding stability coefficient wasessentially unchanged. When the rainfall was heavily and the rainfall was decreased, theanti-sliding stability coefficient of tailings dam was different with the rainfall time. Itshows that the anti-sliding stability coefficient decreased quickly with the intensity ofrainfall.④Based on the GEO-STUDIO software, the paper analyzed the stress field andthe stability of the dam in the conditions of flood and the normal. The results showedthat the vertical displacement of dam was approximately equal to1.8m, and the largestsettlement displacement was appeared at the abutment. The horizontal displacementvalue of flood was slightly larger than the normal condition. The dam’s stabilitycoefficient was2.059, which was obviously less than2.435in the normal condition. Theinteraction force value between bars in the condition of flood was much larger than thenormal due to the different head elevation. The skid stability factor was1.126in thespecial conditions based on the Bishop algorithm, which was greater than the standard1.15and the affluence was not enough. The suggestion of strengthening the constructionof drainage facilities and minimizing the height of Seepage Line was put forward.