Experimental Studies On The Process Of Pillar Failure Based On Acoustic Emission Monitoring

The stability of stope is more important with the mining progress in room-pillar mining. Pillar is a pivotal stope unit and it supports stope, so, it not only ensures stability of roof beam and wall rock, but also stability pillar increases the mining rate of ore body obviously. At present, underground mining is developing toward high stage, high subsection, large scale, trackless in the world, consequently the height of controlling roof increases. The holistic steady behavior of pillar debases markedly with the ratio of height to width increasing. Furthermore, the geometrical shape of pillar is irregular, and rock mass contains various flaws, which influence on the stability of pillar obviously, and the load-carrying capacity decreases of consequently. As mentioned above, the author made a series of physical experiment on different sizes of pillars, who want to explore the deformation and failure process of the pillars during mining, and make preliminary forecast for them.The following aspects are included in this paper:(1) Analyzing the stress and strain characteristic during pillar failure process; Through analyzing the records about the stress and strain, and combining AE location to judging crack initiation, crack propagation and coalescence during rock failure process; analyzing relation to stress (strain), loading time and AE events, which is contributed to study failure character of rock instability process;(2) By AE event location technique, through AE experiment, studying systematically AE activity about pillar; By analyzing the relation to AE activity and rock failure process, discoursing interrelation to AE activity and rock failure and instability;(3) The author paste the graph paper in the specimen surface, and shoot at the same time the specimens original cracks and fracture in loading whole process, Purpose is to read crack length and expand direction of specimens from the graph paper. Finally the author contrast acoustic emission orientation and the photos of the specimens find out the rules of pillar destruction and predict when and where the specimens could break down.