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为了解决高瓦斯采煤工作面上隅角瓦斯积聚和超限的难题,在现有沿空留巷技术的基础上,提出了二次沿空留巷技术。根据二次沿空留巷上覆岩层的活动规律,建立了工作面端头关键块的力学模型,分析了关键块与二次沿空留巷围岩的相互作用机理,引入了关键块的稳定性系数K1,K2,确定了关键块的稳定判据,并推导出巷旁支护阻力计算式。研究结果表明,当K1>1时,关键块发生挤压变形失稳;当K2>1时,关键块发生滑落失稳。以淮南谢一矿512(5)工作面机巷作为工程实例,基于关键块的稳定判据,确定了合理的巷旁充填体宽度,并对关键块的稳定性影响因素进行敏感性分析。实例分析表明,充填体1的终凝强度及其宽度、采高对关键块的稳定性影响较大,提高充填体1的终凝强度、选择合理的充填体1的宽度至关重要,在大采高工作面中进行二次沿空留巷较为困难。
In order to solve the problem of gas accumulation and overrun in the upper corner of the high-gas coal mining face, the secondary gob-side entry retaining technology is proposed based on the existing gob-side entry retaining technology. According to the law of activity of overlying strata in secondary gob-side entry retaining, the mechanical model of the key block at the end of working face is established, the interaction mechanism between the key block and surrounding rock of secondary gob-side entry retaining is analyzed, and the stability of key block The coefficient K1, K2, determine the stability criterion of the key block and deduce the calculation formula of roadside support. The results show that when K1> 1, the key block is buckled and destabilized. When K2> 1, the key block slips out of shape. Taking the 512 (5) face machine lane of Xieyi Mine in Huainan as an example, the reasonable width of lane-side filling body was determined based on the stability criterion of key blocks, and the sensitivity of key block stability was analyzed. The example analysis shows that the final solidification strength, width and height of the filling body 1 have a great influence on the stability of the key block. It is very important to increase the final solidifying strength of the filling body 1 and select a reasonable width of the filling body 1. It is more difficult for secondary gob-side entry in mining face.