垂直溜井中物料的冲击夯实过程及其作用特征

Impact Compaction Process and Its Action Characteristics of Material in Vertical Orepass

垂直溜井卸矿过程中的冲击夯实作用影响着储料矿岩的流动性和井壁的稳定性,也是引起溜井堵塞、井壁失稳的重要因素。针对溜井上部卸矿的冲击夯实作用机理,通过离散元数值模型模拟垂直溜井卸矿过程,分析了冲击夯实作用效果,研究了冲击夯实作用对贮矿段储料内力链结构分布、空隙率和贮矿段井壁侧压力的影响特征。在当前溜井结构参数下,贮矿高度40 m时,研究表明:①冲击夯实作用过程包括下落、碰撞、挤压、反弹、覆盖5个阶段,冲击力依次经过点冲击、面冲击向空间扩展;②应力传递过程中,储料面以下4 m范围内的力链会发生断裂和重组,其余范围的力链被加强或延长,储料整体的力链结构分布变化甚微;③冲击夯实作用对储料面以下5 m范围内的空隙率影响较大,其余范围内的储料空隙率的变化率不到1%;④卸矿过程中,溜井储料面附近井壁会承受较大的冲击作用并造成井壁冲击损伤;同时冲击夯实作用提高了溜井贮矿段中下部的井壁静态侧压力,进而加速井壁磨损和增大悬拱发生率。

The impact-ramming in the process of ore-rock unloading in a vertical orepass affects the fluidity of the orerock and the stability of the orepass wall,and is also an important factor causing the blockage of the orepass and the instability of the shaft wall.Aiming at the action mechanism of impact-ramming during ore-rock unloading from the upper part of orepass,discrete element numerical model is used to simulate the process of ore-rock discharge into a vertical orepass,the influence characteristics of impact-ramming on internal force chain structure distribution,the voidage of stored materials and the wall side pressure of storage section are studied.Under the current orepass structure parameters,when the ore storage height is 40 m,it is found that:①The impact compaction process includes five processes:falling,collision,extrusion,rebounding and covering,and the impact force passes through point impact,surface impact and space expansion in turn.②In the process of stress transmission,only the force chains within 4 m below the storage surface will break and recombine,the force chains in other ranges will be strengthened or extended,and the distribution of force chain structure of the whole storage material changes little.③Impact compaction has a great influence on the viodage within 5 m below the storage surface,and the change rate of storage voidage in other areas is less than 1%.④In the process of ore unloading,the shaft wall near the storage surface of the chute will bear great impact,resulting in the damage of the shaft wall.Impact compaction will also increase the static lateral pressure of the shaft wall in the middle and low part of the ore storage section of the chute,accelerate the wear of the shaft wall and increase the incidence of overhanging arch.