College of Safety Science and Engineering, Liaoning Technical University, Fuxin, Liaoning, China.
Key Laboratory of Mine Power Disaster and Prevention of Ministry of Education, Huludao, Liaoning, China.
PLoS One. 2021 Jul 21;16(7):e0254996. doi: 10.1371/journal.pone.0254996. eCollection 2021.
To study the influence of different factors on the cracking effect of the liquid CO2 phase transition, the mechanics of coal rock crack extension based on liquid CO2 phase change blast loading were studied. Through the application of simulation software to analyze the influence of coal seam physical parameters (in situ stress, gas pressure, modulus of elasticity and strength of coal) and blasting parameters (fracturing pore size and peak pressure of detonation)on the effect of liquid CO2 phase change cracking, the simulation results showed that the cracking effect of liquid CO2 phase change was positively correlated with the changes in gas pressure, elastic modulus, fracture hole diameter and peak vent pressure, negatively correlated with the variation in situ stress and compressive strength, and nearly independent of the tensile strength. In addition, by using Gray correlation analysis to analyze the influence degree of six main factors on the cracking effect, the calculation results showed that the effect of blasting parameters was greater than that of physical parameters. The main controlling factor that affected the blasting effect was the peak pressure of blasting release. By conducting comparative engineering trials with different blasting parameters, the test results showed that the crack effect of the coal seam was positively correlated with the change in fracture hole diameter and peak venting pressure, which was consistent with the results obtained from the simulation. The experimental results and simulation results for the effective radius of coal seam fracturing were basically consistent, with the error between the two types of results falling below 10%. Therefore, the reliability of the blasting numerical model was verified. In summary, the research results provide theoretical guidance for applying and promoting liquid CO2 fracturing technology in coal mines.
为了研究不同因素对液体 CO2 相变致裂效果的影响，研究了基于液体 CO2 相变爆破加载的煤岩裂纹扩展力学。通过应用模拟软件分析煤层物理参数（地应力、气压、弹性模量和煤体强度）和爆破参数（压裂孔径和爆轰波峰压力）对液体 CO2 相变致裂效果的影响，模拟结果表明，液体 CO2 相变致裂效果与气压、弹性模量、裂缝孔径和爆轰波峰压力的变化呈正相关，与地应力和抗压强度的变化呈负相关，与抗拉强度几乎无关。此外，通过使用灰色关联分析分析六个主要因素对致裂效果的影响程度，计算结果表明，爆破参数的影响大于物理参数。影响爆破效果的主要控制因素是爆破释放的峰值压力。通过采用不同爆破参数进行对比工程试验，试验结果表明，煤层的裂缝效果与裂缝孔径和爆轰波峰压力的变化呈正相关，与模拟结果一致。煤层压裂有效半径的试验结果和模拟结果基本一致，两种结果之间的误差低于 10%。因此，验证了爆破数值模型的可靠性。综上所述，研究结果为在煤矿中应用和推广液体 CO2 压裂技术提供了理论指导。
