组合煤岩冲击倾向性演化及声电效应的试验研究

EXPERIMENTAL RESEARCH ON RULES OF ROCKBURST TENDENCY EVOLUTION AND ACOUSTIC-ELECTROMAGNETIC EFFECTS OF COMPOUND COAL-ROCK SAMPLES

在采掘工作面及巷道中,顶板、煤层、底板共同组成一个力学平衡系统,当这个系统受到采动的影响时,就有可能诱发煤岩体所积聚的弹性能通过弱面结构突然释放,形成冲击矿压灾害。因此,研究不同组合类型的顶板–煤样–底板组合试样的冲击倾向性演化及声电效应规律对于监测、预警冲击矿压灾害及强度弱化治理起到非常重要的指导作用。通过大量组合煤岩试样的冲击倾向性及声电效应的试验研究发现,随着煤样强度、顶板岩样强度及其厚度的增加,组合试样的冲击倾向性随之增强,且电磁辐射与声发射信号强度随着组合试样的强度、顶板岩样的高度比例以及冲击能指数的增加而增强。同时发现试样冲击破坏前,声电信号的强度达到极值,冲击破坏之后,信号强度均产生突降。上述研究成果对于指导现场冲击矿压灾害强度的弱化控制以及卸压解危效果的检验具有重要的意义。

In the mining（drifting） faces and roadways, the roof, coal seam and floor all together compose a mechanical equilibrium system. When the system is disturbed by mining effect, the elastic energy accumulated in coal or rock materials can be induced to release through weak structure suddenly and rockburst will be formed. So, to monitor and forecast rockburst, and to deal with strength weakening, the rules of rockburst tendency evolution of different types of compound samples composed of roof, coal seam and floor and acoustic-electromagnetic effect will have a very important practical function. Based on a great number of experimental researches on rockburst tendency and acoustic-electromagnetic effect of compound samples, it is found that the higher the strengths of coal seam and roof samples are, the stronger the rockburst liability is; and the rockburst liability indexes increase with the height ratio of roof to coal. The higher the strength, roof height ratio and rockburst liability indexes of compound samples are, the stronger the intensity of electromagnetic emission（EME） and acoustic emission（AE） signals is. The experimental results also show that the intensity of EME and AE signals rise up slowly before rockburst failure, and increase to the maximum when rockburst precursor, and suddenly decline after rockburst. Above conclusions will have an important directive significance to weaken the strength of rockburst in field and to check the effect of relieve-shot.