本文通过相似材料模拟试验、力学分析、现场研究,指出坚硬顶板二次断裂是客观存在的,二次断裂位置决定了顶板与支护的稳定性。研究表明,二次断裂主要发生在煤壁处和切顶线处、也可能在煤壁前方,其决定于顶板厚度与悬顶距、支护阻力及煤体残余强度,通过支护阻力可以实现二次断裂位置的控制。 In this paper, similar material simulation test, mechanical analysis and field research are carried out. It is pointed out that the secondary failure of the hard roof is objective and the location of the secondary fracture determines the stability of the roof and the support. The results show that the secondary fracture occurs mainly at the coal wall and at the top of the cut line, and may also be at the front of the coal wall, which is determined by the roof thickness, suspended roof distance, supporting resistance and coal residual strength, which can be achieved by supporting resistance Secondary rupture position control.