Study On The Potential Response Characteristics Of Coal Or Rock Damage In Mining

Frequent dynamic catastrophe of rock or coal hampered seriously the efficient production ofmine safety. In recent years, geophysical methods in the study of early warning monitoring ofdynamic catastrophe of rock or coal had been heated up yearly. The monitoring of potential ofcoal or rock had a higher advantages in terms of location monitoring and anti-jamming capabilityand also had good application value and development prospects in the field of dynamiccatastrophe of rock or coal. At present, the research of potential effects special for coal or rock inmining had not been involved. This paper took the mining coal or rock as the object, firstlystudied and analyzed complementally the variation characteristics of surface potential of coaland rock samples under complex stress conditions (friction), then built a coal-rock similarmaterial model, studied the response regularity of the coal rock potential of deformation andfailure under mining conditions; explored the correlation and precursory characteristics ofpotential evolution and rock formation sabotage; developed the mine-used device and system ofpotential testing, conducted a performance measurement, tested and analyzed the variation ofcoal or rock potential under mining in the mine site. The results showed that:(1) The friction process of coal or rock will cause significant changes of potential in thesurface. The potential had a good correspondence with friction stress. The potential signalchanged violently of positive and negative under the friction process of rock, while the surfacepotentials had a small fluctuation and mutated without positive and negative under the frictionprocess of coal samples. The surface potential had an opposite polarity both sides and had a samepolarity on the same side in the friction surface of rock, but the friction surface of coal samplesdidn’t the symmetrical characteristics of potential polarity.(2) The results from the analysis of similar material simulation showed that both the jobs ofexcavation and the move undermine of overlying strata can emerge a potential signal. Thechange of potential signal can reflect the process that the similar seam of coal or rock fractured.In the intermittent period of stop mining, overlying strata emerged reciprocally“unstable-calm-unstable” dynamic change, the potential signal showed alternate change of“active-calm-active” alone with it, and this pattern would be stronger with the expansion of goofscope. The response mode that the potential signal continues high growth and weaken aftersustaining high growth before roof collapse can be as the precursor of roof instable collapse andthe judge basis of roof instable collapse.(3) The coal in the mine site can emerge potential signal under mining conditions. With thesustained advance of mining face, the potential signal that the coal region produced in eachmeasuring point was gradually increased, and the fluctuation range of potential value was gradually increased. The shape of potential curve under mining conditions was similar in acertain degree to the shape of stress distribution of coal and rock before working face. Thechanges of potential in the region could reflect the stress distribution and evolution of coal undermining conditions.The research results provided a foundation based for further research that making use ofcoal-rock potential to monitor the dynamic catastrophe of coal-rock, and had importanttheoretical and practical significance to research of damage evolvement of coal-rock and explorethe warning methods and techniques of potential effect of coal-rock dynamic catastrophe.