基于采空区气体膨胀理论的超大体积采空区综采工作面低氧风险精准预测研究

Research on Accurate Prediction of Hypoxic Risk in Fully Mechanized Mining Faces with Large Volume Goaf Based on Goaf Gas Expansion Theory

根据地面及井下大气压力传感器监测数据,得出地表与井下任意一点气压是同步变化的,井下任意一点与地表的压差是固定不变的。利用该结论分析得出,地表气压下降过程中井下采空区各条漏风通道的漏风量均无明显变化,提出了地表气压下降时采空区内储存的气体发生了膨胀涌出,是导致综采工作面低氧风险加大的原因。通过大量数据统计和理论分析,得出综采工作面低氧仅发生在气压下降的过程中,对于地表漏风量较小的工作面(漏风量不超过120 m^(3)/min),其低氧风险主要取决于大气压力值的大小。对于地表漏风量较大(漏风量大于250 m^(3)/min)的综采工作面,其低氧风险主要取决于大气压力连续下降的幅度。根据天气预报气压预测数据开展了综采工作面每日低氧风险精准预测,预测准确率高达95%以上,同时将低氧风险预测结果用于均压通风管理,使均压系统做到按需启用,在保证了低氧防治效果的同时,有效避免了均压系统过度运行,大大降低了采空区遗煤自燃风险。

According to the monitoring data of surface and underground atmospheric pressure sensors,it is confirmed that the air pressure at any point on the surface and underground changes synchronously,and the pressure difference between any point underground and the surface is fixed.Based on this conclusion,it is concluded that there is no significant change in the air leakage volume of each air leakage channel in the goaf.It is proposed that the gas stored in the goaf expands and gushes out when the surface pressure drops,which leads to the increased risk of hypoxia in the working face.Through a large number of data statistics and theoretical analysis,it is concluded that hypoxia usually occurs in the process of surface air pressure drop.For working faces with small air leakage from surface cracks(air leakage does not exceed 120 m^(3)/min),the hypoxia risk mainly depends on the atmospheric pressure value.However,for fully mechanized mining face with large air leakage from surface cracks(air leakage from surface cracks is greater than 250 m^(3)/min),the hypoxia risk mainly depends on the magnitude of the continuous drop in atmospheric pressure.Based on the weather forecast pressure prediction data,a precise prediction of daily hypoxia risk in fully mechanized mining faces has been carried out.The prediction accuracy rate is more than 95%.At the same time,the hypoxia risk measurement results are used for pressure balancing ventilation management,so that the pressure balancing system can be activated on demand,which greatly reduces the risk of spontaneous combustion of coal left in the goaf.