超临界CO2气爆致裂爆生气体压力沿破裂面变化规律实验研究

为了揭示超临界CO2气爆致裂煤岩体过程中爆生气体压力沿破裂面的变化规律和不同超临界压力对爆生气体压力分布的影响,利用自主研发的超临界CO2气爆实验系统进行爆生气体压力分布测试实验。采用气爆孔周预制弱层的方法,解决了气爆实验传感器难以捕捉裂纹位置的问题。得到了破裂面爆生气体压力与到气爆孔距离和时间的关系式。实验结果表明:气爆过程中破裂面任一点处的爆生气体压力随时间衰减曲线,与气爆孔底爆生气体压力衰减曲线的变化特征相似,服从负指数曲线变化规律,随时间增加,衰减曲线斜率逐渐减小;破裂面任一时刻爆生气体压力,满足近气爆孔处气体压力大于远孔位置的气体压力的规律;随着超临界压力增大,各监测点爆生气体压力峰值增大,相邻监测点压力峰值差增大,监测点达到压力峰值对应时间减小,相邻监测点达到压力峰值的时间间隔变短。

Experimental study of variation pattern of gas pressure from explosion along fracture surface in supercritical CO2 gas explosion

In order to reveal the variation pattern o gas explosion pressure along fracture surface and the influence of different supercritical pressure on the distribution of gas explosion pressure inprocess of supercritical CO2 gas explosion, experimental study of pressure distribution of gas pressure from explosion was carried out by using self-developed supercritical CO2 gas explosion experimental system. By using the method of prefabricating the weak layer around the gas explosion hole, the problem that the gas explosion experiment sensor is difficult to capture the crack position was solved. The relation among gas pressure on the fracture surface, the distance and time to gas explosion hole was obtained. Experimental results show that the gas pressure-time decay curve at any point of fracture surface is similar to the variation pattern of gas pressure decay curve at the bottom of gas explosion hole during the gas explosion process, and which obeys negative exponential curve;with the increase of time, the slope of decay curve decreases gradually. At any moment, the pressure from explosion on fracture surface is more close to above variation pattern for position near the explosion hole than that from farther position. With the increase of supercritical pressure, the gas pressure peak at each monitoring point increases, the differential value of pressure peak between adjacent monitoring points increases, the time while monitoring point reaches the peak pressure becomes shorter, the time interval that the adjacent monitoring point reaches the pressure peak becomes shorter.