预裂辅助冲击截齿的破煤特性

近年来我国煤炭资源持续性大规模开采,如今国内的整体煤炭开采难度与日俱增,硬质煤层和黏性煤层的比例增加是制约煤炭开采效率的主要因素,而传统机械破煤技术很难实现硬煤、黏煤的高效截割。因此针对传统截齿在硬质和黏性煤岩破煤效果不佳的问题,从煤壁辅助预裂与截割相结合的角度出发,利用理论分析和数值模拟的方法研究了冲击预裂与截齿截割煤岩破碎特性,在综合考虑实际工作中的牵引、回转与冲击运动,提出了截齿运动轨迹模型,建立了预裂辅助冲击截齿的破煤轨迹数学模型,得到了截齿破煤运动轨迹的解析解。并根据分析结果建立了预裂辅助冲击截齿与传统截齿的单截齿滚筒破煤离散元模型,从破煤颗粒实际占比、破煤难易程度、截齿受力波动等角度对两种截齿的破煤特性进行了对比分析。研究结果表明:在破煤颗粒实际占比上,预裂辅助冲击截齿在煤体硬度同为f6时提高了31%,当黏度黏聚力为2.6 MPa时预裂辅助冲击截齿的效率提升接近14%;在破煤难易程度上,预裂辅助冲击截齿在硬度值为f6时可降低50%的破煤难度,当黏度黏聚力为1.88 MPa时,预裂辅助冲击截齿可降低约12%的难度;在截齿受力波动上,预裂辅助冲击截齿在硬质煤或黏性煤均能够减小近7 000 N的力,因此,开展预裂辅助冲击截齿的研究,将有利于破碎硬质和黏性等特殊煤岩介质。

Coal breaking characteristics of presplitting assisted impact pick

In recent years,the continuous large scale mining of coal resources in China has made the overall coal mining more and more difficult.The increasing proportion of hard coal and viscous coal is the main factor restricting the efficiency of coal mining.However,the traditional mechanical coal breaking technology is difficult to achieve an efficient cutting of hard coal and viscous coal.Therefore,aiming at the problem of poor coal breaking effect of traditional pick in hard and viscous coal and rock,starting from the angle of combination of auxiliary presplitting and cutting of coal,the characteristics of impact presplitting and cutting of coal and rock are studied by means of theoretical analysis and numerical simulation.Considering the traction,rotation and impact movement in actual work,the motion trajectory model of pick is put forward and the presplitting is established.The mathematic model of coal breaking trajectory of presplitting assisted impact pick is established,and the analytical solution of coal breaking trajectory of pick is obtained.Based on the analysis results,the discrete element model of coal breaking of presplitting assisted impact pick and single pick drum with traditional pick is established.The coal breaking characteristics of the two kinds of pick are compared and analyzed from the aspects of the actual proportion of coal breaking particles,and the degree of difficulty in the coal breaking and force fluctuation of the pick.The results show that in coal breaking efficiency,the presplitting assisted impact pick increases 36% when the hardness of coal is f6.When the cohesive force is 2.6 MPa,the efficiency promotion of the presplitting assisted impact pick is close to 14%.In the difficulty of coal breaking,the presplitting assisted impact pick can reduce the difficulty by 50% when the hardness is f6.When the cohesive force is 1.88 MPa,the presplitting assisted impact pick can reduce the difficulty of about 12%.In the force fluctuation of the pick,the presplitting assisted impact pick can reduce the force of nearly 7 000 N in the hard coal or the viscous coal.Therefore,the study of the presplitting assisted impact pick will be beneficial to the crushing of the special coal rock medium such as hard and viscous.