单一粗颗粒影响下的松动体形态演化特征试验研究

Experimental study on shape evolution characteristics of IMZ under influence of single coarse particle

在崩落矿岩颗粒流动过程中,粗颗粒的存在会影响散体的运移特性和规律。针对现有放矿研究中未充分考虑粗颗粒影响的问题,基于自主设计的矿岩颗粒体系非接触式放矿监测与分析系统开展一系列放矿试验,对比手动圈绘与Image Pro Plus(简称IPP)软件圈绘这2种方式所得松动体(IMZ)形态及松动体高度与最大半径的关系,从定性和定量两个方面验证IPP圈绘在放矿试验中的可靠性,并探究粗颗粒对松动体形态及其四周细颗粒运移特性的影响。研究结果表明:IPP软件可更高效、便捷地自动圈绘松动体。粗颗粒会对四周局部细颗粒位移产生显著影响,且相较于上方细颗粒,粗颗粒对下方细颗粒的影响更大。当松动体经过粗颗粒时,粗颗粒上方局部区域颗粒位移由幂律分布转变为Logistic分布,粗颗粒下方局域区域颗粒位移由幂律分布转变为波动的无规律分布。单个粗颗粒会对松动体局部形态产生显著影响。当松动体边界经过粗颗粒时,松动体局部形态出现凹陷及不连续弯曲现象。当模型中普通颗粒粒径为3~8 mm时,粗细颗粒粒径比dc/df大于6.0的粗颗粒会引起松动体的形态发生变化。粗颗粒的存在会提高四周细颗粒达到放矿口的速度,其上、下方局部区域分别有17.02%和31.42%的颗粒提前达到放矿口。

In the process of particle flow of caving ore and rock,the existence of coarse particles will affect the migration characteristics and law of loose body.In view of the problem that influence of coarse particles is not fully considered in the existing drawing research,a series of drawing tests were carried out based on the self-designed non-contact drawing monitoring and analysis system of ore rock particle system.By comparing the shape of isolated movement zone(IMZ)and the relationship between the height of IMZ and the maximum radius obtained by manual circle drawing and IPP circle drawing,the reliability of IPP software in ore drawing test was verified from both qualitative and quantitative perspectives.The influence of coarse particles on the shape of IMZ and the migration characteristics of fine particles around it were explored.The results show that IPP software can automatically draw loose body more efficiently and conveniently.Coarse particles will have a significant impact on the displacement of local fine particles,and the effect of coarse particles on the fine particles below is greater than that of upper fine particles.When the IMZ passes through the coarse particles,the particle displacement in the local area above the coarse particles changes from power-law distribution to logistic distribution,and the particle displacement in the local area below the coarse particles changes from power-law distribution to fluctuating irregular distribution.A single coarse particle will have a significant impact on the local morphology of IMZ.When the boundary of IMZ passes through coarse particles,the local shape of IMZ displays depression and discontinuous bending.When the diameter of ordinary particles in the model is 3−8 mm,coarse particles with a diameter ratio of coarse to fine particles dc/df greater than 6.0 will cause morphological changes in IMZ.The existence of coarse particles will increase the speed of fine particles around reaching the ore drawing mouth,and 17.02%and 31.42%of the particles in the upper and lower local areas reach the ore drawing mouth in advance.