离子型稀土矿抗剪强度指标特征及影响因素

Analysis on Shear Strength Index Characteristics and Influencing Factors of Ionic Rare Earth Ore

由于离子型稀土矿通常采用原地浸矿工艺,降低了矿岩的抗剪强度,从而诱发边坡失稳。利用固结不排水试验、不固结不排水试验和快剪试验,研究不同初始干密度、初始含水率和孔隙溶液类型下矿体抗剪强度指标的变化规律。结果表明:当初始含水率一定时,矿体的黏聚力与初始干密度呈正相关,内摩擦角随初始干密度变化不大;当初始干密度一定时,矿体的黏聚力与初始含水率呈负相关,内摩擦角随初始含水率增加略微增大;在不同初始干密度、含水率影响下Ccu和C′呈良好的线性关系;当初始干密度、含水率一定时,CU试验、UU试验与快剪试验的C、φ值大小关系分别为:Cq>Cuu>Ccu,φcu≈φq。研究结果为离子型稀土在无氨氮或少氨氮开采工艺中矿山边坡的稳定性评价提供一定的理论指导。

The in-situ leaching process used in ionic rare earth ore often reduces the shear strength of the mine and induces slope instability.Through consolidated undrained(CU)test,unconsolidated undrained(UU)test and fast shear test,the variation laws of shear strength index of ore body under different initial dry densities,initial water contents and pore solution types were studied.The results are concluded as follows.When the initial moisture content is constant,the cohesion of ore body is positively correlated with the initial dry density,and the internal friction angle changes little with the initial dry density.When the initial dry density is constant,the cohesion of the ore body is negatively correlated with the initial water content,and the internal friction angle increases slightly with the increase of the initial water content.Under the influences of different initial dry densities and water contents,there is a good linear relationship between Ccuand C′.When the initial dry density and water content are constant,the relationship between C andφof CU test,UU test and fast shear test is:Cq>Cuu>Ccu,φcu≈φq.The research results can provide a theoretical guidance for the slope stability evaluation of ionic rare earth ore in the mining process without ammonia nitrogen or less ammonia nitrogen.