为了对煤层底板突水进行预测,基于煤岩在压力作用下有微震信号产生,提出利用自行设计的微震全波形综合监测试验系统对干燥煤岩和含水煤岩变形破裂过程微震信号的变化规律进行研究。结果表明:煤岩变形破裂过程可分为压实阶段、线弹性变形阶段和破裂发展阶段,在破裂发展阶段微震信号事件数和信号强度迅速增加;随着加载速度的增大煤岩的峰值强度增大,煤体产生微震信号事件数增多,大振幅的微震信号事件也增多,出现应力下降即煤岩形成较大裂隙时产生强度较大的微震信号;但饱和含水煤岩的峰值强度和煤岩冲击倾向性比自然干燥煤岩都低,且微震信号事件数和信号强度都降低。上述结论对指导现场煤层底板突水的预警有重要意义。
In order to predict the water- inrush in coal seam floor,based on the microseismic signals generation of coal and rock under pressure,the variation laws of microseismic signals during the deformation and fracture process of dry and water-containing coal and rock were studied by using the self- designed microseismic full waveform comprehensive monitoring test system. The results showed that the deformation and fracture process of coal and rock can be divided into compression stage,elastic deformation stage and fracture development stage. The event number and strength of microseismic signals increase rapidly in the stage of fracture development. With the increase of loading speed,the peak strength of coal and rock increases,the event number of microseismic signals produced by coal increases,as well as the event number of large amplitude microseismic signals,and the stronger microseismic signals appear when the stress drop occurs,namely larger cracks of coal and rock come into being. Both the peak strength and rockburst tendency of saturated moisture- containing coal and rock are lower than those of natural dry coal,and both the event number and the strength of microseismic signals reduce. The above conclusions have great significance to guide the early- warning of coal seam floor water- inrush in the field.