不同端壁倾角条件下放出体形态研究及最优崩矿步距的确定

为分析端部放矿中放出体形态,获得大结构参数下最优的崩矿步距,基于颗粒元理论和PFC3D程序,构建具有矿石散体细观力学性质的放矿模型. 通过已有研究结论与模拟结果的对比分析,验证了基于PFC程序的放矿模型的可靠性. 在此基础上,开展18m×20m结构参数下不同端壁倾角崩矿步距研究. 研究结果表明,不同倾角端壁条件下放出体形态不完整,并不是一个规则的椭球体. 当放矿量相同时,放出体高度随端壁倾角的减小而增大,放出体整体形态也随之越来越"瘦长".在无限边界和不同倾角端壁条件下,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. 建议在18 m × 20 m结构参数下采用85°~90°的端壁倾角,4. 8 m的崩矿步距.

Research of the isolated extraction zone form and determination of optimal independent advance under different end wall angles

In order to analyze the form of the isolated extraction zone ( IEZ) in side drawing and get optimal independent advance with large structural parameters, drawing models with the mesomechanical properties of ore granular media were constructed based on the particle flow theory and PFC3D code. The reliability of the drawing models was validated by comparative analysis between existing research conclusions and simulated results. On this basis, a study on independent advance of side drawing at different end wall angles in the structural parameters of 18 m × 20 m was performed. The results show that the IEZ form is incomplete and is not a regular ellip-soid at different end wall angles. When the drawn mass is equal, the IEZ height increases with decreasing end wall angle and the IEZ form becomes more and more slender. The trend of the IEZ height at both the infinite boundary condition and the boundary condition of different end wall angles can be divided into two stages:in the first stage, the IEZ height rapidly increases in the exponential form at the initiation of side drawing and its growth rate decreases with the increasing of drawn mass, while in the second stage the IEZ height linearly increases with the increasing of drawn mass. It is suggested that the end wall angle of 85°-90° and the independent advance of 4. 8 m should be used in the structural parameters of 18 m × 20 m.