为研究急倾斜特厚煤层综放工作面顶板的破断规律,以乌东煤矿北采区45°倾角煤层为研究对象,根据简支梁理论建立了急倾斜特厚煤层综放开采条件下顶板的受力模型,得到顶板的力矩方程,分析基本顸破断位置,对破断后的基本顶基于悬臂梁理论建立力学模型,得到顶板的拉应力方程,分析不同回采环境下基本顶破断长度,同时采用3DEC软件对不同回采环境下顶板破断长度进行数值计算.结果表明:急倾斜特厚煤层综放开采在充分采动条件下顶板中部最先破断;随着基本项厚度的增加,基本顶的破断长度呈线性减小;随着回采段高的增加,基本顶的破断比呈抛物线增加.现场采用钻孔窥视,获得基本顶的破坏情况,监测结果和理论分析基本一致,为后续的项板“注水-爆破”耦合钻孔位置提供科学依据,对于煤矿的顶板灾害防治有重要意义.%In order to study on the roof breaking law of fully-mechanized top coal caving face in steep and ultra thick coal seam.Taking the 45° coal seam in the northern mining area of Wudong Coal Mine as the research object.In this paper,the stress model of the roof under fully-mechanized top coal caving face in the steep and ultra thick seam was established,the moment equation of the roof was obtained,the basic top breaking position was analyzed,and then the basic roof was established based on the theory of cantilever beam.Stress equation was used to analyze the basic breaking length in different mining environments.At the same time,3DEC software was used to calculate the breaking length of roof under different mining conditions.The results showed that the fully-mechanized top coal caving in the steep and ultra thick seam had the first break in the middle.With the increases of the basic roof thickness,the breaking length of the basic roof decreased linearly.With the increase of the height of the mining section,The breaking ratio was increased by parabola.The useing of drilling on the scene peep,accessed to the basic top of the damage,monitoring results and theoretical analysis were same,for the roof monitoring and protection of coal was important.
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