The non-pillar entry (roadway) retained by roof cutting serves the two adjacent working faces. As compared with the conventional mining roadways, the roadway retained by roof cutting has a longer life cycle and receives more complicated influence from mining. Determining the location where the roof deformation and maximum deformation occur can provide an important basis for roadway support. Here, the direct roof of the roadway is studied by assuming it as an elastic deformation body. The stress features of the direct roof of the gob-side entry retained by roof cutting are analyzed, and the roof deformation is divided into five stages. The stress superposition principle is employed, and the equivalent concentrated load within the roadway is introduced. The mechanical model of the direct roof is established for the whole process of gob-side entry retaining by roof cutting. Next, the calculation formula for the concentration of direct roof at different positions is obtained for the whole process of gob-side entry retaining by roof cutting. The application scope of the calculation formula and the determination method of the key parameters are analyzed. The relationship between direct roof deformation of the roadway and stiffness of the support system is studied. The results show that the direct roof deformation has a symmetrical distribution about the midline. The maximum roof deformation occurs in the middle of the roadway, and it gradually decreases as the coal seam stiffness increases. During the example calculation, the maximum roof deformation is 280 mm for the gob-side entry retaining under primary mining. The measured maximum roof deformation is 320 m, and the error rate is 12.5%. It is then verified that the uniform mechanical model proposed in this study applies to the calculation of direct roof deformation in the gob-side entry retained by roof cutting.

中文翻译：

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切顶无柱留空全过程直接顶板力学结构研究

屋顶切割保留的无柱入口（巷道）服务于两个相邻的工作面。与常规采矿巷道相比，顶板切割保留的巷道具有更长的生命周期，并受到更复杂的开采影响。确定顶板变形和最大变形发生的位置可为巷道支护提供重要依据。在这里，通过假设它是一个弹性变形体来研究道路的直接屋顶。分析了顶板切割保留的沿空区直接顶板的应力特征，将顶板变形分为五个阶段。采用应力叠加原理，引入巷道内等效集中荷载。建立了顶板切割沿空留巷全过程的直接顶板力学模型。其次，推导出顶板截留沿空留空全过程不同位置直接顶板浓度的计算公式。分析了计算公式的适用范围和关键参数的确定方法。研究了巷道顶板直接变形与支护系统刚度的关系。结果表明，直接顶板变形在中线附近呈对称分布。最大顶板变形发生在巷道中部，随着煤层刚度的增加逐渐减小。在示例计算过程中，初级开采下沿空留巷的最大顶板变形为280 mm。实测最大屋顶变形为320 m，误差率为12.5%。然后验证了本研究提出的均匀力学模型适用于顶板切割保留的沿空空域直接顶板变形的计算。