基于覆岩破坏传递的超前自卸压区影响宽度研究*

为确定超前自卸压区的宽度，将其更好地应用于边采边抽钻孔布置中，探讨影响超前自卸压范围的主要因素，揭示卸压区宽度与工作面超前支承压力的内在联系，根据压力拱曲线平移特性，提出在覆岩破坏传递过程中，冒落带随回采周期性垮落，造成超前支承压力重分布，简化工作面开采模型，推导计算卸压区宽度的理论新方法并进行现场试验验证。结果表明:通过实测采面前方顺层钻孔的瓦斯抽采纯量，确定超前自卸压区宽度为28~30 m；距工作面＞20~40 m范围为卸压瓦斯高效抽采区，平均瓦斯抽采纯量0.074 m³/min，为卸压前的3.89倍；考虑覆岩破坏传递的超前自卸压区宽度计算值为29.97 m。计算值与实测结果较吻合，验证该方法的可行性，为井下卸压区高效抽采提供借鉴。

Study on influence width of advanced self-relief pressure zone based on overburden failure transmission

To determine the width of the advanced self-relief pressure zone and better apply it to the layout of boreholes while mining with gas drainage,the main factors affecting the range of advanced self-relief pressure were discussed,and the internal relationship between the width of pressure relief zone and the advanced support pressure of working face was revealed.According to the translational characteristics of the pressure arch curve,it was proposed that during the process of overburden failure transmission,the caving zone periodically collapsed with the mining,resulting in the redistribution of the advanced support pressure.After simplifying the mining model of working face,a new theoretical method for calculating the width of pressure relief zone was derived,and the field test verification was conducted.The results showed that through measuring the pure quantity of gas drainage of the bedding boreholes in front of the mining front,the width of the advanced self-relief pressure zone was determined to be 28~30 m.The range of ＞20~40 m away from the working face was the high-efficiency drainage area of pressure relief gas,and the average gas drainage pure quantity was 0.074 m3/min,which was 3.89 times of that before pressure relief.Considering the overburden failure transmission,the calculation value of the width of advanced self-relief pressure zone was 29.97 m,which was in good agreement with the measured results and verified the feasibility of this method.It provides a reference for the high-efficiency drainage in the underground pressure relief zone.