采动裂隙发育规律和支架荷载变化规律是软弱薄基岩放顶煤安全开采的两个关键问题,以淮北朱仙庄煤矿薄基岩区综放工作面为研究对象,采用物理模拟、理论分析、现场实测等方法对这两个问题进行了深入研究。研究结果表明:软弱薄基岩中的黏土质矿物较多,在地下水的长期作用下,极易发生风化崩解、膨胀,有效地阻隔了采动裂隙的发育,放顶煤开采时裂采比为3.6~5.4,裂隙带发育高度远远小于正常厚度基岩,且基岩越薄,裂隙发育高度受阻现象越明显;薄基岩在风化作用下,力学性质大大弱化,煤层顶板中无基本顶承载层,支架工作阻力远远小于额定工作阻力,来压步距远小于正常基岩,来压显现不明显。 The law of mining fissure development and the variation of support load are two key issues in the safe mining of soft roof caving coal in soft thin bedrock. Taking the fully mechanized top caving mining face in thin bedrock area of ​​Zhu Xianzhuang coal mine in Huaibei as the research object, the physical simulation and theoretical analysis are used Measured and other methods on these two issues in-depth study. The results show that there are many clay minerals in soft thin bedrock, which are prone to disintegrate and expand by weathering under long-term action of groundwater, effectively blocking the development of mining fractures, Is 3.6 ~ 5.4, the development height of fissure zone is far less than that of normal bedrock, and the thinner the bedrock, the more obvious the fissure development is blocked. The mechanical properties of thin bedrock are greatly weakened by weathering, and there is no basic roof bearing Layer, stent work resistance is much less than the rated working resistance to pressure step is much smaller than normal bedrock, to show obvious pressure.