Wang Xu, Tian Chenglin, Wang Qingbiao, Shi Zhenyue, Sun Yong, Wang Keyong
College of Resources, Shandong University of Science and Technology, Taian, 271019, Shandong, China.
National Engineering Laboratory for Coalmine Backfilling Mining, Shandong University of Science and Technology, Taian, 271019, Shandong, China.
Sci Rep. 2025 Jan 15;15(1):2080. doi: 10.1038/s41598-025-85296-5.
Because coal seam mining with high geostress and high gas pressure is prone to coal-rock-gas compound dynamic disasters, a disaster energy equation considering the influence of roof elastic energy is established, and a disaster energy criterion considering the influence of roof elastic energy is derived and introduced into COMSOL software to conduct numerical simulations of coal seam mining under different geostress and gas pressures. The study revealed that the increase of ground stress reduces the gas pressure required for disaster occurrence. When the gas pressure reaches a certain value, the disaster will occur even if the ground stress is very small. When the ground stress and gas pressure are very low, by changing the magnitude of ground stress or gas pressure, outburst, rockburst and coal‒rock‒gas composite dynamic disasters can transform into each other. As the depth of the excavated coal seam increases, the geostress‒gas pressure increases from 15‒0.5 MPa to 20‒0.74 MPa and 25‒1 MPa, the peak stress and peak gas pressure can reach maximum values of 39.61 MPa and 1.11 MPa, respectively, the difference between the elastic energy of the coal rock body and the expansion energy of the gas is not large, and the energy criterion is greater than 1 and increasing, which indicates that the occurrence of a compound dynamic disaster and the degree of hazard gradually increase. The high-pressure water jet slit technology can increase the average gas extraction volume by 3.6 times, the peak stress is transferred from 7 m away from the coal wall to 10 m, and the peak stress is transferred to the deep coal wall, which can effectively reduce the stress in the coal rock mass and the gas pressure in the coal seam.
由于高地应力和高瓦斯压力条件下的煤层开采容易引发煤岩瓦斯复合动力灾害，建立了考虑顶板弹性能影响的灾害能量方程，推导了考虑顶板弹性能影响的灾害能量判据，并将其引入COMSOL软件，对不同地应力和瓦斯压力条件下的煤层开采进行数值模拟。研究表明，地应力增加会降低灾害发生所需的瓦斯压力。当瓦斯压力达到一定值时，即使地应力很小也会发生灾害。当地应力和瓦斯压力都很低时，通过改变地应力或瓦斯压力的大小，突出、冲击地压和煤岩瓦斯复合动力灾害可以相互转化。随着开采煤层深度增加，地应力-瓦斯压力从15-0.5MPa增加到20-0.74MPa和25-1MPa，峰值应力和峰值瓦斯压力分别可达最大值39.61MPa和1.11MPa，煤岩体弹性能与瓦斯膨胀能之差不大，且能量判据大于1且呈增加趋势，表明复合动力灾害的发生及危害程度逐渐增大。高压水射流割缝技术可使平均瓦斯抽采量提高3.6倍，峰值应力从距煤壁7m处转移到10m处，并向深部煤壁转移，可有效降低煤岩体应力和煤层瓦斯压力。
