Research On Safety Of Fine Tailings Dam Under The Influence Of Saturation Line Distribution Characteristics

The safety operration of tailing spond always plays a significant role in the whole mining production. With the tailings particle size is becoming smaller and smaller and the fill dam is higher and higher, the stability of tailings dam is becoming worse and worse, so the stability of fine-grained tailings dams has become the key and hot spot in the tailing dam engineering. According to incomplete statistics, about25%of tailings dam accident were caused by the failure control of seepage and the high position of saturation line, so the saturation line is also called the lifeline of the tailings dam. The tailings dam accident can not only bring great losses to people’s life property, but also destroy the environment seriously, therefore, studying the morphological characteristics of saturation line and its role in tailing dam safety has high academic value and significant economic and social benefits.In this paper, The Ji Guanshan taiing dam is taked as the research object, the tailings of physical and mechanical properties are tested to obtain its mechanical parameters. By theoretical study and numerical simulation, the saturation line and stability of the tailing dam body with different heights and different operation conditions were calculated and analyzed, and the ralationship between saturation line morphological characteristics and dam body stability were studied. The main works done and the conclusions obtained in this paper are as follows:(1) By reading massive references, the paper made a systematic summarization on sedimentary regularity of fine-grained tailings, and analyzed its engineering characteristics from the aspect of consolidation characteristic, strength characteristics and permeability, besides, the paper posed problems existing in fine-grained tailings dams.(2) The paper expounded systematically the saturated-unsaturated seepage theory, and analyzed water movement in unsaturated soil and saturated soil, obtained control equation and definite conditions of saturated-unsaturated seepage.(3) With the numerical software SEEP/W, this paper calculated the seepage of Ji Guanshan tailing dam to get saturation line of the dam body in different height and different operation conditions separately, and anlyzed the change law of the saturation line morphological characteristics. Based on the limit equilibrium theory, by substitution of the data obtained from seepage calculation into soft SLPOE/W to analyze dam body stability, and to get assumed sliding surface, at the same time, the Critical Slip Field method was used to search the failure surface and evalute its stability for dam body, and resluts by these two method were compared.(4) Three-dimensional numerical model was established by MIDAS program, to analyze the stability of fine-grained tailings dam in current height and design height, to get the law of dam body stress and strain.Aiming at possible problems in later damming project, some measures about reinforcing safety management and security technology are proposed to ensure the whole dam body stability.