【摘要】 为提高电磁辐射预测煤岩体动力灾害的准确性,采用室内试验和分形理论相结合的方法研究单轴压缩煤体产生的电磁辐射分形特征。研究结果表明:煤岩体受载过程中产生的电磁辐射脉冲数在时间上具有明显的分形特征,分形维数与煤样的冲击能指数成正幂指数关系;当受载煤岩体处于压密阶段时电磁辐射分形维数较小;处于弹性阶段时,电磁辐射分形维数有一个较小增长,并保持在一个稳定的水平;当受载煤岩体处于塑性阶段时,电磁辐射分形维数大幅度提高;临近主破裂时电磁辐射逐渐降低;主破裂时电磁辐射分形维数降低到最低水平;残余变形阶段,电磁辐射分形维数先增长后减少,总趋势减少。利用上述研究成果,成功地对7249工作面的冲击地压进行准确的预测预报。实践表明,计算脉冲数分形维数的电磁辐射法能够预测煤岩动力失稳现象。更多还原

【Abstract】 To improve accuracy of forecast of coal and rock mass dynamic disasters by using electromagnetic emission (EME),the EME fractal characteristics of coal samples during uniaxial compression test are studied by laboratory experiments and fractal theory. The results show that the EME impulses have fractal characteristics;and the fractional dimension has a positive power exponential relationship with the impact energy exponent of coal samples. When the loaded coal samples are at the stage of consolidation,the fractional dimension of EME is small;at the stage of elasticity,the fractional dimension of EME has a little increase and remains at a stable level; at the stage of plasticity,the fractional dimension of EME increases greatly;close to main fracture,the fractional dimension of EME decreases gradually;at the main fracture,the fractional dimension of EME decreases gradually;and at the stage of residual deformation,the fractional dimension of EME firstly increases and then decreases,and general trend of the fractional dimension is declining. Based on the above studies,the rock burst has been forecasted accurately and successfully in working face 7249. The practice shows that the EME method which calculates the fractional dimension is feasible to forecast the dynamic disasters in mines.更多还原