细粒含量对尾矿工程性质影响分析

由长期工程实践和试验研究可知，尾矿的工程性质除与尾矿的矿石成分、筑坝方式以及矿浆的沉积特性有关外，重要的是与尾矿的颗粒粒度组成有关。为了分析上游式尾矿库尾矿经排放、沉积、分选等作用下颗粒组成的变化特征及其对尾矿工程性质的影响规律，通过对上游式尾矿库沉积滩面不同距离处尾矿进行颗粒级配分析、力学性质和渗透性质试验，重点分析了细颗粒含量（颗粒直径小于0.075 mm）对尾矿工程性质的影响规律。研究表明，随着距离上游式尾矿库滩顶长度的增大，尾矿颗粒组成中的细粒含量逐渐增多，颗粒级配情况由一般到良好再到一般，孔隙比也呈现出随之先减小后增大的变化趋势。受原尾矿颗粒组成的影响，尾矿黏聚力随细粒含量的增加呈逐渐增大，而内摩擦角相对变化较小，其渗透系数受细颗粒含量影响较大，随含量增大迅速减小。

Effect of fines content on engineering characteristics of tailings

Long-term experience of practical applications and lab tests implies that the engineering characteristics of tailings is related to some factors such as mineral composition, damming layout, sedimentary characteristics of the ore pulp, and more closely to the particle size distribution of tailings. In order to analyze the upriver-type tailings variations of the particle composition and its influence on the tailings engineering properties after discharging, depositing, sorting, a series of tests is performed to determine the particle-size distribution, mechanical properties and permeability of tailings at different positions on depositional beach face, and the influence of the fine particles (particle diameter less than 0.075 mm) content on the engineering properties of tailing is analyzed. It is found that as the distance from the tailings beach crest increases, the composition of fine particle gradually increases, grain size distribution situation changes from normally to well-graded, then again normally-graded; void ratio initially decreases and then increases; the tailings cohesion grows gradually as the content of fine particles increases, whereas internal friction angle changes within a relatively small range; the permeability coefficient is significantly influenced by the fine particle content, and decreases rapidly with the increase of the content.