水分对煤力学性能及冲击能量指数的影响研究

    Study on the effect of moisture on mechanical properties and impact energy index of coal

    • 摘要: 煤的破坏是能量驱动下的一种失稳现象,为探究水分对煤破坏过程中能量积聚与耗散的影响,开展了不同含水状态煤样的单轴压缩试验,并基于此对煤的力学性能及冲击能量指数进行分析。结果表明:随含水率的增加,煤样单轴抗压强度和弹性模量显著降低;煤样的初始压密阶段、塑性变形破坏阶段及峰后破坏阶段在全应力-应变过程中的占比均增大,线弹性阶段占比减小;煤样峰前积聚变形能减小,峰后损耗变形能升高,冲击能量指数降低;含水率增加使煤样由劈裂破坏转变为剪切破坏,在破坏时崩落的碎块粒径变大,碎块数量减少,破坏声响减弱;饱水状态下煤样较干燥状态煤样单轴抗压强度、冲击能量指数及冲击能量速度指数分别下降35.32%、86.07%、99.63%;采用煤层注水工艺能有效降低煤层冲击倾向性。

       

      Abstract: Coal destruction is an energy-driven destabilization phenomenon. In order to investigate the effect of moisture on energy accumulation and dissipation during coal destruction, uniaxial compression tests on coal samples with different water content states were carried out, and the mechanical properties and impact energy index of coal were analyzed based on this. The results showed that the uniaxial compressive strength and elastic modulus of coal samples decreased significantly with the increase of water content; the proportion of the initial compression-density stage, plastic deformation damage stage and post-peak damage stage in the full stress-strain process of coal samples increased, and the proportion of linear elastic stage decreased; the accumulation deformation energy before the peak of coal samples decreased, the loss deformation energy after the peak increased, and the impact energy index decreased. The increase of water content changed the coal sample from splitting damage to shear damage, and the particle size of crumbling pieces became larger, the number of pieces decreased, and the damage sound weakened during the damage. The uniaxial compressive strength, impact energy index and impact energy velocity index of coal samples in water-saturated condition decreased by 35.32%, 86.07% and 99.63%, respectively, compared with those in dry condition, and the coal seam water injection process can effectively reduce the impact propensity of coal seam.

       

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