尾矿浆沉积室内模拟试验

尾矿浆的沉积特性对尾矿坝的坝体结构有重要影响.为了研究尾矿浆的沉积分层特征和时间演化规律,对黏性尾矿浆和砂性尾矿浆进行一维沉降柱试验,讨论了尾矿沉积物的细观结构特征和分层划分依据,分析了沉积物形态与时间的关系,并用双电层理论解释了絮凝作用对沉积特征的影响机理.结果表明:尾矿黏粒具有颗粒细小、黏土矿物成分比例高和吸附性强的特点,在液体环境下易形成高孔隙率的絮状结构体;根据细观结构的变化,尾矿沉积层从上到下依次分为澄清区、絮凝区、沉降区和固结区;按时间划分,可以将尾矿的沉积过程分为沉降阶段和固结阶段,黏性尾矿的沉积时间大约是砂性尾矿的2倍;砂性尾矿的沉积时间主要由单颗粒的自由沉降速度决定,黏性尾矿浆的沉积过程可用分界面高度-时间的函数关系来描述.研究结果揭示了尾矿浆的沉积过程和细观结构之间的联系,为尾矿浆沉积规律的预测提供了参考.

Indoor scale-down test of tailings

The sedimentary rule of tailings slurry has an important influence on dam structure. In this paper, the sediment forma-tion characteristics and evolution law of tailings slurry were investigated through a unidimensional sedimentation experiment. The meso-scopic structure and stratigraphic classification of tailings sediment were discussed, the relationship between morphology and time was analyzed, and the electric double-layer theory was used to explain the influence of flocculation on the sedimentary characteristics. The experimental results show that, compared with sand particles, clay particles are smaller in size, contain more clay minerals and have better adsorption, and form a high-porosity flocculent structure in a liquid environment. With respect to the changes in the mesoscopic structure, tailings sediment can be divided into a water zone, flocculation zone, subsidence zone, and consolidation zone. The process of sedimentation can be divided into subsidence and consolidation stages along the time axis and the deposition time of the clayey tail-ings is about twice that of sandy tailings. The sedimentation time of the sandy tailings mainly depends on the free subsidence velocity of single particles, whereas the sedimentation process of clayey tailings can be described as a function of the interface level and time. This research findings lay a theoretical foundation for correlation research of the sedimentary process and mesoscopic structure, which provide a reference for the prediction of fine-grained tailings compression deformation.