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为揭示煤体强度对煤与瓦斯突出的影响机制,开展了3组不同强度含瓦斯型煤瞬间揭露致突模拟试验,借助高速录像技术与气体压力高速采集技术,精确获取了突出瞬间0.5 s以内的试验数据。结果表明突出型煤的破坏形式及瓦斯压力变化特征与未突出型煤相比存在差异。突出型煤由揭露口向内呈现口小腔大的粉碎破坏并随瓦斯气体抛出,瓦斯压力下降速率高达2.5 MPa/s,且存在粉煤与瓦斯高速涌出阶段和残余瓦斯缓慢涌出阶段2个阶段。未突出型煤仅在揭露口附近少许破碎,无粉煤瓦斯流喷出,瓦斯压力下降速率在0.01~0.02 MPa/s之间,趋于稳定后仍高于大气压力。试验表明型煤强度对突出起阻碍作用,型煤单轴抗压强度与突出瓦斯压力呈二次函数关系,与突出孔洞深度呈线性负相关关系。在突出的孕育阶段,当总应力相同时,型煤强度越低、瓦斯压力越高,越容易发生破坏,并通过煤体有效应力强度理论分析了其影响机制。分析计算了型煤弹性能和瓦斯内能,突出型煤瓦斯内能占比大,而未突出型煤弹性能占比大,二者能量释放的差异是煤体强度影响煤与瓦斯突出的本质原因。
In order to reveal the mechanism of the influence of coal mass on coal and gas outburst, three groups of experiments were conducted to reveal the sudden burst of gas containing coal briquette with different intensities. With high-speed recording technology and high-speed gas pressure acquisition technology, Of the experimental data. The results show that there are differences between the failure mode of protruding briquette and the variation characteristics of gas pressure compared with non-protruding briquette. Outburst briquette is exposed inwardly from the exposed mouth and is thrown with gas gas. The gas pressure drop rate is as high as 2.5 MPa / s, and there is a period of gush of pulverized coal and gas at high speed and a slow gush of residual gas 2 stages. The unobvious briquette only crushed a little in the vicinity of the exposing mouth and no powder coal gas flow was ejected. The gas pressure descending rate was between 0.01 and 0.02 MPa / s, which was still higher than the atmospheric pressure after stabilizing. Experiments show that the briquette strength hinders the protrusion, the biaxial compressive strength of briquette and the outburst gas pressure show a quadratic function, and there is a linear negative correlation between the briquette depth and the protruding hole depth. In the prominent stage of gestation, when the total stress is the same, the briquette strength is lower, the gas pressure is higher, the more prone to damage, and the effect mechanism is analyzed based on the effective stress intensity of coal. Analysis and calculation of briquette energy and gas internal energy, the prominent coal gas energy to account for a large proportion of non-prominent bombs, the proportion of large energy performance, the difference between the two energy release is the impact of coal strength coal and gas outburst nature the reason.