浅埋旺采工作面厚层坚硬顶板裂纹产生至大面积冒落时间差研究

Study on the time difference from initiating cracking to large area caving of thick-hard roof on shallow Wongawilli face

神东矿区浅埋深厚层坚硬顶板地质条件和旺采工艺致使工作面采空区顶板极易形成大面积悬顶,当工作面一个区段刚刚回采至极限面积时,厚层坚硬顶板可能会大面积垮落造成设备损坏、人员伤亡。论文运用断裂力学理论,从裂纹扩展的能量平衡观点出发,推算出了理想状态下,无爆破扰动的情况下,厚层坚硬顶板旺采面采空区达到极限面积之后顶板从破坏到垮落的最短时间,为厚硬顶板合理控制提供了理论依据。

The geological condition of shallow thick-hard roof is very common in Shendong mining area, which would be particularly conductive to form a large area hanging roof especially when the Wongawilli production practice is adopted. If one of the working face sections stopped to limit area, large-area caving zone will come into being on the thick-hard roof, which will result in casualties and equipment damage. In this paper, fracture mechanics theory is adopted to study the cracking of thick-hard roof. Based on energy balance in the process of crack extension, the minimum duration from initiating cracking to large area caving of thick-hard roof on Wongawilli face under ideal conditions without blasting disturbance is derived, and it provides a theoretical basis for reasonable control of thick-hard roof.