卸矿高度对溜井卸矿冲击夯实作用效果的影响

Influencing of unloading height on impact ramming effect in the process of orepass unloading

溜井卸矿过程中矿岩的冲击夯实作用会引发溜井堵塞、井壁损伤等问题,影响矿山安全高效生产。卸矿高度是影响溜井卸矿冲击夯实作用效果的主要因素之一。为探究其影响特征,以孔隙率变化量、井壁冲击力峰值作为评判标准分别表征卸矿对储料的夯实效果和对井壁的冲击效果,采用PFC 2D建立了溜井卸矿数值模型,模拟了6种卸矿高度下的冲击夯实作用过程,分析了卸矿高度对孔隙率变化量、井壁应力峰值的影响特征。研究发现:①储料孔隙率变化量、井壁冲击力峰值与卸矿高度呈正相关,与所测量范围到储料面的距离呈负相关;②降低卸矿高度可以减小卸矿过程中的夯实范围及效果,在贮矿段直径6 m、贮矿高度24 m等条件下,距离储料面5 m范围内随着卸矿高度降低,对储料的夯实效果也明显减弱,其余范围内夯实效果受影响程度较小;③降低卸矿高度可以减小卸矿对井壁的冲击效果,在当前溜井结构参数下,储料面以下9 m范围内井壁冲击力峰值受卸矿高度的影响程度显著,其余范围内受影响程度较小;④矿山可采用降低卸矿站与溜井贮矿段储料面间的高度落差、减少一次卸矿量、支护井壁等措施降低或预防冲击夯实作用对溜井系统带来的负面影响。

During the unloading process in orepass,the impact and compaction of ore rock will cause orepass blockage,shaft wall damage and other problems,which will affect the safe and efficient production of mine.The unloading height is one of the main factors that affects the impact ramming effect of orepass unloading.To explore the effects characteristics of the process,take porosity variation and peak impact force on shaft wall as the standard,respectively represents the tamping effect of ore unloading on the storage material and the impact effect on the shaft wall.A numerical model of orepass unloading is established by PFC 2D to simulate the process of impact compaction under six unloading heights.On the basis of this,the influence characteristics of unloading height on the variation of porosity and the peak stress of shaft wall are analyzed.The conclusions are as follows.The change of storage porosity and the peak value of sidewall impact force are positively correlated with the unloading height and negatively correlated with the distance from the measured range to the storage surface.Reducing the height of ore unloading can reduce the tamping range and effect in the process of ore unloading.Under the conditions of the diameter of the storage section 6 m and the storage height 24 m,within the range of 5 m from the material storage surface,with the reduction of the unloading height,the tamping effect on the material storage is also significantly weakened,and the tamping effect in the remaining range is less affected.Lowering the height of ore unloading can reduce the impact of ore unloading on the shaft wall.Under the current structural parameters of the orepass,the peak value of the impact force of the shaft wall in the range of 9 m below the storage surface is significantly affected by the unloading height,while the influence degree is small in the other ranges.The mine can reduce the height drop between the unloading station and the ore storage surface of the ore storage section of the orepass,reduce single ore discharge,supporting the shaft wall and other measures to reduce or prevent the negative impact of impact compaction on the orepass system.