水岩作用下不同强度煤岩组合体力学特性损伤规律研究

Study on Damage Law of Mechanical Properties of Coal-Rock Mass with Different Strength Under Water-Rock Interaction

在富水矿井中,煤岩体以及井下留设的隔水煤岩柱受到地下水的长期侵蚀,导致煤岩体在水岩作用下力学特性发生改变并受到损伤,直接影响到矿井的稳定及安全生产。因此,对泥岩-煤-泥岩(N-M-N)、砂岩-煤-砂岩(S-M-S)、石灰岩-煤-石灰岩(H-M-H)3种不同煤岩强度比的煤岩组合体开展饱水前和饱水后的单轴压缩试验,研究水岩作用下煤岩组合体的力学特性演化规律和声发射损伤特征,并结合RFPA2D数值模拟分析水岩作用对组合体破裂形式的影响。研究结果表明:水岩作用对煤岩组合体抗压强度和弹性模量有明显的劣化效应;水岩作用使煤岩组合体的声发射计数和累计计数下降明显;水岩作用使煤岩组合体裂隙扩展及破裂形式发生明显改变,声发射事件数始终伴随有裂隙的产生与扩展。

In water-rich mines, coal-rock mass and underground water-resisting coal pillar are eroded by groundwater for a long time, which will cause the change and damage of mechanical properties of coal-rock mass under water-rock interaction, directly affecting the stability of the mine and the safe production. Therefore, uniaxial compression tests of mudstone-coal-mudstone(N-M-N), sandstone-coal-sandstone(S-M-S), and limestone-coal-limestone(H-M-H) with three different strength ratios of coal-rock mass were carried out before and after water saturation. The evolution laws of mechanical properties and acoustic emission damage characteristics of coal-rock mass under water-rock interaction were studied. And the influence of water-rock interaction on the failure form of coal-rock mass was analyzed by RFPA2D numerical simulation. The results show that water-rock interaction has an obvious deterioration effect on compressive strength and elastic modulus of coal-rock mass. And the acoustic emission count and cumulative count of coal-rock mass decrease obviously due to water-rock interaction. And the water-rock interaction makes the fracture propagation and failure form of coal-rock mass change obviously, and the number of acoustic emission events is always accompanied by the generation and distribution of fractures.