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由于地下水对隔水煤柱和地下水库边界的反复浸水损伤,研究反复浸水对煤样的裂隙损伤作用有助于解决中国西部干旱区半干旱区矿区井下储水以及含水层煤柱留设问题。通过自制浸水装置制取干燥,浸水1次,2次,3次,4次的煤样共5组,分别进行单轴压缩声发射实验。研究表明,煤样的峰值应力、弹性模量随着煤样浸水次数的增加而呈现不同程度的减小,但峰值应变随着浸水次数的增加而变大。刚度应力曲线结合声发射累计计数曲线能阐明裂隙发育的各个阶段,随着反复浸水次数增加,煤样裂隙的闭合应力阈值,裂隙初始发育阈值和裂隙损伤阈值均线性减小,但3个阈值占峰值强度的比值不随着浸水次数改变而变化,其比值分别为15.52%,31.04%和67.81%。实验结果对矿区地下水库建立和隔水煤岩体留设以及探究煤样裂隙发育规律具有指导意义。
Due to repeated groundwater damage to the percolation pillar and the boundary of the underground reservoir, studying the effect of repeated flooding on the fracture damage of coal samples is helpful to solve the problem of downhole water storage and coal pillar retention in semi-arid area of west China. Through self-made water immersion device, five groups of coal samples were obtained, which were dried, immersed in water for 1, 2, 3 and 4 times, respectively. Uniaxial compression acoustic emission experiments were carried out. The results show that the peak stress and elastic modulus of coal sample decrease with the increase of coal sample immersion times, but the peak strain increases with the increase of immersion times. The stiffness stress curve combined with the acoustic emission cumulative counting curve can clarify the various stages of fracture development. With the increase of repeated immersion times, the closure stress threshold, initial fracture initiation threshold and fracture damage threshold decrease linearly, but the three thresholds The ratio of peak intensity does not change with the number of immersion, the ratio was 15.52%, 31.04% and 67.81% respectively. The experimental results have instructive significance for the establishment of underground reservoirs and the construction of water-separated coal and rock mass and the exploration of the law of fracture development of coal samples.