• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
微波辐射降低硬煤冲击倾向性试验研究
  • Title

    Experimental investigation on decreasing burst tendency of hard coal using microwave irradiation

  • 作者

    胡国忠王春博许家林吴旭飞秦伟

  • Author

    HU Guozhong,WANG Chunbo,XU Jialin,WU Xufei,QIN Wei

  • 单位

    中国矿业大学 江苏省矿山地震监测工程实验室中国矿业大学 矿业工程学院中国矿业大学 煤炭资源与安全开采国家重点实验室

  • Organization
    Jiangsu Engineering Laboratory of Mine Earthquake Monitoring and Prevention,China University of Mining and Technology; School of Mines,China University of Mining and Technology; State Key Laboratory of Coal Resources and Mine Safety,China University of Mining and Technology
  • 摘要

    如何有效地改变煤岩体物理力学性质是冲击地压防治领域亟待解决的关键难题,而微波致裂弱化法是解决这一难题的新途径。为探究微波致裂弱化法降低硬煤冲击倾向性的实效性,采用自主研制的微波辐射试验装置与C46.106型MTS电液伺服试验机,开展了煤体微波致裂弱化试验,研究了微波辐射对煤体的动态破坏时间、冲击能量指数、弹性能指数、单轴抗压强度和纵波波速的影响规律,确定了降低煤体冲击倾向性的最优微波参量范围;在此基础上,研究了微波辐射下冲击倾向煤体的损伤致裂效应,分析了微波对煤体的热效应、煤体损伤因子与微波参量之间的变化关系,揭示了煤层巷道微波致裂弱化防冲机理。结果表明:① 微波致裂弱化法能有效降低或消除煤体冲击倾向性。煤体微波致裂后,煤样峰值强度大幅下降,应力-应变曲线峰后段应力降增多,使峰前积聚的总能量降低且分级释放,煤体由脆性向塑性转变;同时,煤样载荷-时间曲线峰后段表现出多台阶、分级跌落的特征,煤体积蓄的弹性能减少,从而导致煤体各项冲击倾向指标均有不同程度降低。② 微波辐射对煤体的减冲效果表现为能量阈值现象,而在微波能量恒定条件下高功率-短时间的能量组合更有利于煤体减冲。③ 微波对煤体内各矿物的选择性热效应使煤体产生热破裂,表现为煤样表面出现多条纵向裂缝以及与之垂直的分支裂隙。④ 煤样冲击倾向性与煤样纵波速度存在显著相关性。微波能量及其辐射强度越大,煤体纵波波速降幅越大,则煤体冲击倾向性越小。⑤ 煤巷微波致裂弱化防冲机理在于,通过增大冲击地压发生的临界塑性软化区半径,引起巷道围岩高应力区向深部转移,提高巷道围岩塑性软化区对弹性区释放能量的耗散能力;同时,煤体峰后软化模量显著降低,导致冲击地压发生的临界载荷增大,从而降低巷道发生冲击地压的可能性。

  • Abstract

    How to effectively change the physical and mechanical properties of coal and rock mass is an urgent problem to be solved in the field of prevention and control of rock burst,and the microwave fracturing weakening method is a new way for solving this problem.To explore the effectiveness of the microwave fracturing weakening method to reduce the burst tendency of hard coal,a test of microwave fracturing weakening on coal is carried out based on the self developed microwave irradiation device and C46.106 MTS electro hydraulic servo experimental machine.The influence of microwave irradiation on the parameters such as dynamic failure time,impact energy index,elastic energy index,uniaxial compressive strength and P wave velocity of coal is studied,and the optimal microwave parameter range to reduce the burst tendency of coal is obtained.On this basis,the damage fracturing effect of the coal with burst tendency under microwave irradiation is studied.Also,the relationship between the selective heating effect of the microwave on the minerals in the coal,the coal damage factor and the microwave parameters are analyzed.The mechanism of reducing burst risk of the surrounding coal of the roadway is revealed by using microwave fracturing weakening.Research results show that the method of microwave fracturing weakening can effectively reduce or eliminate the burst tendency of coal.After microwave fracturing on coals,the peak load of coal samples drops significantly,and the stress drop in the post peak section of the stress strain curve increases,which reduces the total energy accumulated before the peak and is released slowly by stages.The coal changes from brittle failure to plastic deformation.Simultaneously,the coal samples before the peak of the load time curves shows the characteristics of multiple steps and graded drops,and the elastic energy stored in the coal mass is reduced,so that the burst tendency indicators of the coal are reduced to some degrees.The effect of the microwave irradiation on the burst tendency reduction of coals is manifested as an obvious energy threshold phenomenon.Under the condition of equal microwave energy,the energy combination of high power short time is more conducive to weaken the burst tendency of coals.The selective heating effect of microwave on the various minerals in the coal results in thermal cracking of the coal,which is manifested as appearing multiple longitudinal cracks and branch cracks perpendicular to it on the surface of the coal samples.Research results show a remarkable correlation between the burst tendency and the P wave velocity of the coal samples.The greater the microwave energy,the greater the reduction in P wave velocity of the coals,and the smaller the burst tendency of the coals.The mechanism of microwave fracturing weakening on coal to prevent the rock burst of coal roadway is to increase the radius of the critical plastic softening zone where rock burst occur,causing the high stress in the surrounding rock of the roadway can be transferred to the deep part,thereby improving the ability of the surrounding rock plastic softening zone of the roadway to dissipate the energy released by the elastic zone.Simultaneously,the pre peak softening modulus of coals is significantly decreased,which leads to an increase in the critical load for rock burst,thereby reducing the possibility of rock burst in roadways.

  • 关键词

    冲击地压冲击倾向性微波致裂弱化法热破裂微波参量

  • KeyWords

    rock burst;burst tendency;the method of microwave fracturing weakening;thermal fracturing;microwave parameters

  • 基金项目(Foundation)
    国家自然科学基金资助项目(51774279);江苏高校“青蓝工程”资助项目;江苏省“六大人才高峰”高层次人才资助项目(JNHB-094)
  • 引用格式
    胡国忠,王春博,许家林,等.微波辐射降低硬煤冲击倾向性试验研究[J].煤炭学报,2021,46(2):450-465.
    HU Guozhong,WANG Chunbo,XU Jialin,et al.Experimental investigation on decreasing burst tendency of hard coal using microwave irradiation[J].Journal of China Coal Society,2021,46(2):450-465.
  • 相关专题
  • 图表
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    • 微波辐射后煤样的单轴抗压强度冲击等级分布

    图(16) / 表(0)

相关问题

主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会

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