煤矿开采动力灾害事故分析及防治对策研究

Analysis of coal mining dynamic disasters and study on prevention countermeasures

为进一步研究煤矿开采动力灾害发生的机理,预防和减轻煤矿开采动力灾害事故,通过对3起煤矿瓦斯、煤岩动力灾害事故相关技术参数和现场勘察分析,结合张集矿1152(3)回风巷顶板应力转移测定结果,分析了煤岩层结构特征、断层构造带、多因素耦合、采掘应力重新分布与动力灾害发生的关系。研究表明:原岩地应力和构造地应力的共同作用是产生能量积聚,地应力集中的主导因素,构造破坏带两侧一定范围弹性能富积,应力集中,特别容易发生动力灾害事故。坚硬顶板是应力传递转移的载体,完整顶板会加大集中应力的形成及加剧事故的扩大,掘进工作面前方5~10 m为采动应力集中区。在软硬交替煤岩结构条件下,局部地段软弱煤体受压变形弹性能积聚,加之煤体耦合富积瓦斯,降低了始突能量,采掘作业应力重新分布,易诱发煤岩或煤与瓦斯动力灾害事故,且大多数形成二次或多次集中应力(能量)卸放转移,造成能量扩展叠加,导致动力灾害范围或危害性扩大。做好地应力、瓦斯压力、钻屑指标法等冲击动力参数指标测定,通过开采保护层卸压或预裂爆破人工切断坚硬顶板,避免应力集中并切断应力传递途径,可达到减少冲击动力事故发生的目的。

In order to further study the mechanism of coal mining dynamic disaster,prevent and reduce coal mining dynamic disaster accident,through the analysis of relevant technical parameters and field investigations of three coal mine gas and coal rock impact dynamic disaster accidents,combined with the measurement results of stress transfer change distribution of No.1152(3)return air entry roof in Zhangji Coal Mine,the relationship between coal and rock structure characteristics,fault structure belts,multi-factor coupling,redistribution of mining stress and the occurrence of dynamic disasters were analyzed.The results show that the combined effect of in-situ stress and tectonic stress is the leading factor of energy accumulation and in-situ stress concentration.The elastic energy is abundant and the stress is concentrated in a certain range on both sides of the structural failure zone,which is especially prone to dynamic disaster accidents.The hard roof is the distribution carrier of stress transfer.The complete roof will increase the formation of concentrated stress and aggravate the expansion of accidents.The mining stress concentration area is 5 to 10 m in front of the development work.Under the condition of soft and hard alternating coal rock structure,the elastic energy of local soft coal body under compression deformation is accumulated,and the coal body is coupled with rich gas,which reduces the initial outburst energy.The redistribution of mining stress will induce the occurrence of coal or coal and gas dynamic disaster accidents,most of which form secondary or multiple concentrated stress(energy)release and transfer,resulting in energy expansion and superposition,leading to the expansion of the scope of dynamic disaster or hazard.In order to avoid stress concentration and cut off the stress transmission path,the impact dynamic parameters such as in-situ stress,gas pressure,drilling cuttings index method and other impact dynamic parameters should be measured.The hard roof can be cut off manually by pressure relief or pre-splitting blasting to avoid stress concentration and cut off the stress transmission path,which can effectively prevent the impact dynamic disasters and achieve the goal of reducing the occurrence of impact power accidents.