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以阜新同乃铁矿排放的铁尾矿为研究对象,经试验得出其级配不良,属于含砂低液限粉土。通过室内试验分析了不同含水率和压实度条件下铁尾矿的抗剪强度。结果表明,铁尾矿的抗剪强度与其含水率和压实度之间有很大的相关性。相同压实度条件下,黏聚力随含水率升高呈先增大后减小的规律,存在特征含水率,在特征含水率条件下黏聚力达到最大值。黏聚力与含水率可近似拟合为二次函数。土颗粒间的水膜联结和胶结作用对黏聚力的产生具有重要作用,黏聚力因含水率的不同而变化较大。试验得出含水率变化对铁尾矿内摩擦角的影响较小,这是因为砂土的内摩擦角与砂土的颗粒结构、大小及密实程度密切相关,而铁尾矿中的粗粒含量较高,含水率变化不会引起其颗粒结构、大小及密实程度的显著变化。在相同含水率条件下,铁尾矿的黏聚力和内摩擦角均随压实度增大而呈近似线性增大。不同含水率和压实度条件下,铁尾矿的黏聚力均不大,铁尾矿的抗剪强度主要依靠内摩擦角的贡献。考虑铁尾矿材料的抗剪强度因压实度和含水率不同而变化,可使尾矿库稳定性分析结果更符合实际情况。
Taking the iron tailings discharged from Fuxin Tonga Iron Mine as the research object, it was found that the grading of the iron tailings was bad and belongs to the low liquid limit silt with sand. The laboratory tests were conducted to analyze the shear strength of iron tailings with different water content and compaction. The results show that there is a significant correlation between the shear strength of iron tailings and its moisture content and compaction degree. Under the same degree of compaction, the cohesion increases first and then decreases with the increase of water content, and the characteristic moisture content exists, and the cohesion reaches the maximum under the characteristic moisture content. Cohesion and moisture content can be approximately fitted to a quadratic function. The water film bonding and cementation between soil particles play an important role in the cohesion, and the cohesion changes greatly due to the different moisture content. The results show that the variation of water content has little effect on the internal friction angle of iron tailings because the internal friction angle of sand is closely related to the grain structure, size and compactness of sand, while the coarse content of iron tailings Higher, moisture content changes do not cause significant changes in their particle structure, size and density. Under the same moisture content, the cohesion and internal friction angle of iron tailings increase linearly with the increase of compaction degree. Under different moisture content and compaction degree, the cohesion of iron tailings is not large, and the shear strength of iron tailings mainly depends on the contribution of internal friction angle. Considering that the shear strength of iron tailings varies with the degree of compaction and water content, the result of tailings stability analysis can be more in line with the actual situation.