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以晋华宫煤矿坚硬厚层顶板条件为工程背景,通过理论分析与现场实测相结合,研究了厚层坚硬顶板的临界失稳条件、失稳方式、影响失稳的因素以及失稳的机理,提出了厚层坚硬顶板失稳控制的方法.研究表明,岩层自身属性及赋存特点对坚硬厚层顶板破断后的承载具有重要影响;坚硬厚层顶板断裂失稳的发展受顶板断裂长度的影响显著,而提高支架支护强度对顶板断裂失稳的控制作用是有限的;提出对厚层顶板实施爆破预裂减小顶板断裂长度和合理支架选型提高支架支护强度相结合的顶板控制方法.通过在晋华宫煤矿8210工作面的应用实施,工作面支架末阻力与时间加权阻力分别占额定工作阻力的85.3%与83.7%,工作面顶板随采随垮,煤壁片帮深度控制在0.2～0.3m范围.
Taking the hard and thick roof conditions of Jinhuagong Mine as the engineering background, the critical instability conditions, the instability modes, the factors affecting the instability and the instability mechanism of thick and hard roof are studied through the combination of theoretical analysis and field measurements. The method to control the instability of thick and hard roof is put forward.The research shows that the properties and occurrence features of the rock have an important influence on the bearing of the roof and the roof after it is fractured. The development of the fracture and instability of the roof is affected by the length of the roof, And the control effect of supporting strength of support on the failure of roof is limited. The roof control method which combines blasting pre-cracking on thick roof to reduce the length of roof fracture and reasonable support selection to improve support strength of support is proposed Through the application and implementation of 8210 working face in Jinhuagong Coal Mine, the final resistance and the time weighted resistance of working face support accounted for 85.3% and 83.7% of the rated working resistance, respectively. The roof of the working face collapsed with the mining and the depth of coal wall slab was controlled at 0.2 ~ 0.3m range.