单一粗颗粒对矿岩颗粒体系剪切特性影响试验

为了探究不同垂直压力以及不同粒径、形状和位置的单一粗颗粒对矿岩颗粒体系抗剪强度和运移特性的影响，采用自主设计的矿岩颗粒体系非接触式剪切特性监测与分析系统开展直接剪切试验.研究结果表明，当形状因子>0.5时，添加粗颗粒会显著增加5～10 mm矿岩颗粒体系的抗剪强度，粗细颗粒粒径比为3.07～4.23.粗颗粒在剪出口时的矿岩颗粒体系抗剪强度最大，剪入口次之，位于可视面中心位置时的抗剪强度最小.在所研究的取值范围内，矿岩颗粒体系抗剪强度随着垂直压力的增加呈线性增长规律.当形状因子<0.5时，随着粗颗粒形状因子的增加，抗剪强度无显著变化，当形状因子≥0.5时，随着粗颗粒形状因子的增加，抗剪强度缓慢增加.相较于粗颗粒形状，垂直压力对矿岩颗粒体系抗剪强度的影响更显著.在所研究的取值范围内，不同粗颗粒粒径、形状和垂直压力影响下的四周细颗粒运移轨迹均符合Boltzmann分布.粗颗粒四周细颗粒的垂直位移随着粗颗粒形状因子的增加会显著增加，随着垂直压力的增加，则会降低四周细颗粒的垂直位移；粗颗粒形状因子和垂直压力的二者增加均会提高细颗粒运移轨迹方向的有序程度.

Experimental study on influence of single coarse particle on shear properties of ore-rock particle system

A self-designed ore-rock particle system non-contact shear characteristics monitoring and analysis system was adopted to conduct direct shear tests in order to analyze the influence of single coarse particle with different vertical pressures and different sizes, shapes and positions on the shear strength and migration characteristics of the ore-rock particle system. The research results were as follows. The addition of coarse particles significantly increased the shear strength of the 5-10 mm ore-rock particle system when the shape factor was larger than 0.5, where the coarse to fine particle size ratio ranged from 3.07 to 4.23. The shear strength of the ore-rock particle system was the largest when the coarse particle was at the shear exit, followed by the shear entrance, and the shear strength was the smallest when it was located at the center of the visible surface. The shear strength of ore-rock particle system increased linearly with the increase of vertical pressure within the range of studied values. The shear strength had no significant change with the increase of coarse particle shape factor when the shape factor was less than 0.5. The shear strength increased slowly with the increase of coarse particle shape factor when shape factor was greater than or equal to 0.5. The effects of vertical pressure on the shear strength of ore-rock particle system were more significant compared with the shape of coarse particle. The migration trajectories of fine particles around under the influence of different coarse particle size, shape and vertical pressure all correspond to Boltzmann distribution within the range of values studied. The vertical displacement of fine particles around coarse particle will significantly increase with the increase of coarse particle shape factor, and decrease with the increase of vertical pressure. The increase of coarse particle shape factor and vertical pressure will improve the order of fine particle migration trajectory.