含红土层薄基岩工作面突水溃砂机制与影响因素模拟研究

Simulation study on the mechanism and influencing factors of water and sand inrush in the working face of thin bedrock with laterite layer

针对煤矿松散含水层下薄基岩工作面顶板发生切落,导致突水溃砂灾害事故,以陕西省郝家梁煤矿30108工作面突水溃砂灾害事故为背景,从理论上分析突水溃砂的发生机理,通过数值模拟方法再现了在基岩厚20 m、红土层厚40 m、开采高度6.5 m、推进20 m左右时工作面发生突水溃砂的过程,并进行了影响因素分析。研究发现,在薄基岩、厚红土层条件下,红土层的自身特性对裂隙带的发育有明显的抑制作用,导水裂隙带发育不完整、不充分,但是在多个相邻工作面连续开采的过程中,红土层强度受采动影响和水的渗透侵蚀作用而逐渐降低,裂隙带高度逐渐发育升高,当红土层强度降低约47%时,后续工作面开采过程中顶板易发生切落导致突水溃砂事故。进一步模拟发现,除红土层自身特性外,影响覆岩破坏导致工作面突水溃砂的主要因素还包括基岩厚度、红土层厚度、开采高度等。因此,系统研究导致矿井发生突水溃砂的机理以及主要影响因素对类似条件矿井预防同类事故发生具有重要的现实意义。

In response to the roof of a thin bedrock working face under a loose aquifer in a coal mine being cut off,resulting in the water and sand inrush disaster,taking the 30108 working face of Haojialiang Coal Mine in Shaanxi Province as the background,the mechanism of water and sand inrush is theoretically analyzed. Through numerical simulation methods, the process of water and sand inrush in the working face is reproduced when the bedrock is 20 meters thick, the laterite layer is 40 meters thick, the mining height is 6.5 meters, and the advance is about 20 meters. And an analysis of influencing factors is conducted. The research has found that under the conditions of thin bedrock and thick laterite layer, the inherent characteristics of laterite layers have a significant inhibitory effect on the development of fracture zones, the development of water conducting fracture zones is incomplete and insufficient. However, during the continuous mining of multiple adjacent working faces, the strength of laterite layer gradually decreases due to the influence of mining and water infiltration erosion, and the height of the fracture zone gradually increases. When the strength of laterite layer reduces by about 47%, the roof is prone to cutting and causing water and sand inrush accidents. The further simulation indicates that, in addition to the inherent characteristics of the laterite layer, the main factors affecting the water and sand inrush in the working face caused by overburden failure also include bedrock thickness, laterite layer thickness, mining height. Therefore, studying the mechanism of water and sand inrush and the main influencing factors is of great practical significance for preventing similar accidents in mines under similar conditions.