瓦斯压力对采场支承压力的影响及突出-冲击协同防控

    Influence of gas pressure on abutment stress and prevention of gas-rockburst composite disaster

    • 摘要: 随着煤炭开采深度和强度的增大,部分矿井面临煤与瓦斯突出与冲击地压双重灾害威胁,突出-冲击复合灾害成为值得关注的科学与工程难题,含瓦斯煤体采动支承压分布规律对于揭示该类型灾害机理具有重要意义。通过研究瓦斯压力变化对采动支承压力分布的影响,建立了含瓦斯煤体支承压力计算模型,得到了含瓦斯压力变化的切向应力以及塑性区半径计算公式;基于典型突出-冲击矿井工程地质条件,采用数值模拟得到了瓦斯压力对采场支承压力分布的影响特征。结果表明:随着瓦斯压力减小,巷道周边切向应力增加,而塑性区半径减小,即切向应力峰值距离煤壁更近;采场支承压力峰值与瓦斯压力负相关,峰值距煤壁距离与瓦斯压力呈正相关,均表现为二次曲线关系。现场监测数据表明,随着瓦斯抽采的进行,煤体破裂震动频次上升,当出现瓦斯压力持续下降、而震动频次急剧上升趋势时,冲击危险性较高。基于瓦斯压力变化对冲击危险的影响,建立了海石湾煤矿突出-冲击协同防控技术体系,在瓦斯治理过程,利用瓦斯压力-震动频次预警冲击危险,并优化防冲卸压工程的起始位置与强度,实现突出-冲击协同防控。

       

      Abstract: With the increase in the depth and intensity of coal mining, some coal mines encounter the dual disaster threat of gas outburst and rockburst, and the composite gas-rockburst disaster has become a scientific and engineering problem that deserves more attention, and the distribution of abutment stress is of great significance for revealing the mechanism of composite dynamic disasters. This paper focuses on the influence of gas pressure on the abutment stress, establishes a theoretical model of a circular roadway and obtains the influence of gas pressure changes on the tangential stress and the radius of the plastic zone. The influence characteristic of gas pressure on the front abutment of a longwall working face is simulated based on the typical engineering geological conditions of an outburst-rockburst mine. The results show that as the gas pressure decreases, the tangential stress around the roadway increases, and the radius of the plastic zone decreases, meaning that the peak tangential stress is closer to the roadway. The peak abutment stress is negatively correlated with the gas pressure, while the distance of the peak from working face is opposite, both showing a quadratic relationship. On-site monitoring shows that as gas extraction proceeds, the frequency of mining-induced tremors increases significantly. When there is a sharp upward trend of the mining-induced tremors along with the continuous decrease of gas pressure, the risk of rockburst is high. A gas-rockburst coordination prevention and control technology system is established in Haishiwan Coal Mine based on the relationship of gas pressure changes and rockburst danger. During the gas control process, the gas pressure-microseismicity frequency is used to predict the rockburst risk and optimize the starting position and strength of destress engineering to achieve collaborative prevention and control of outburst-rockburst.

       

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