多放矿口条件下崩落矿岩流动特性

基于离散元理论和PFC3D程序构建放矿模型,探究多放矿口条件下崩落矿岩流动特性,实现多放矿口条件下放出体及矿石残留体形态变化过程的可视化.同时,将模拟结果与已有研究结论进行对比分析,验证基于PFC程序的放矿模型在崩落矿岩流动特性研究中的可靠性.放矿PFC模拟结果表明,多放矿口条件下放出体形态会因各放矿口间的相互影响而产生交错、缺失等程度的不同变异,并不是一个规则的椭球体.在单一放矿口和多放矿口条件下,放出体高度的变化趋势均可概括为两个阶段:在放矿初始阶段,放出体高度呈指数形式快速增加,随放矿量的增加,其增长率逐渐减小;随后,放出体高度将随放矿量的增加而呈线性增长的趋势.矿石损失率随放矿口尺寸及崩落矿石层高度的增大而减小,随放矿口间距的增大而增大.当相邻放矿口间产生相互影响时,平面放矿方式与立面放矿方式相比,其矿石残留量更小,且崩落矿岩接触面呈近似水平状态下降. 

Flow characteristics of caved ore and rock in the multiple draw-point condition

Based on the particle flow theory and PFC3D code,a draw model was constructed to research the flow characteristics of caved ore and rock in the multiple draw-point condition and visualize the form-changing process of the isolated extraction zone(IEZ) and the ridge hangover body. Simultaneously,the suitability and reliability of this draw model were validated in the flow characteristics study of caved ore and rock by comparative analysis between simulated results and existing research conclusions. Due to interactions among multiple draw-points,the IEZ's form produces different degrees of variation in the multiple draw-point condition,including interlacement and deficiency,which result in that the IEZ's form is not a regular ellipsoid. The height changing trend of the IEZ in both the isolated draw-point condition and the multiple draw-point condition can be divided into two stages:in the first stage,the IEZ's height rapidly increases in an exponential form at the initiation of draw and its growth rate decreases with the increase of ore-drawn mass; in the second stage,the IEZ's height linearly increases with the increase of ore-drawn mass. The ore loss ratio decreases when the draw-point dimension and the height of the caved ore layer increase,but it increases with the increasing of draw-point spacing.When adjacent draw-points interact with each other,compared with a facade draw mode,the ridge hangover mass is less in a plane draw mode,and the contact surface of caved ore and rock horizontally drops.