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针对被动法煤层瓦斯压力测定过程中平衡时间和准确度问题进行分析研究,研究发现被动法瓦斯压力测定过程中只要存在气体交换面,即可测得瓦斯压力,同时通过建立模型进行计算发现钻孔成孔过程中,球向钻孔卸压半径远小于径向钻孔,故瓦斯损失较小,按照极限平衡理论,理论平衡时间较短,测定的压力值要略高即准确度较高。经数值模拟计算证明了上述计算的正确性,并且发现自由排放时间越长,球向钻孔占径向钻孔平衡时间的百分比越小,平衡时间优势越明显。经现场实践证明被动法瓦斯压力测定过程中球向钻孔在平衡时间和准确性上优势明显。
In view of the analysis of balance time and accuracy in the process of passive coal seam gas pressure measurement, it is found that the gas pressure can be measured as long as the gas exchange surface exists in the process of passive gas pressure measurement. Meanwhile, by establishing the model, In the process of forming a hole, the relief radius of the ball hole is much smaller than that of the radial hole, so the gas loss is small. According to the theory of limit equilibrium, the theoretical equilibrium time is short, and the measured pressure value is slightly higher, ie, the accuracy is higher. The correctness of the above calculation is verified by numerical simulation, and the longer the free discharge time, the smaller the percentage of radial borehole radial borehole equilibrium time, the more obvious the balance time advantage. The field practice proved that passive gas pressure during the determination of ball to the hole in the balance of time and accuracy of the obvious advantages.