By regarding the immediate roof as the deformable medium and based on the compatible deformation mechanism of the immediate roof and main roof, a mechanical analysis model was established, and the functional relation between the periodic weighting distance of the main roof and the parameters of immediate roof was derived under the given deformation condition of the main roof. Analysis was carried out on the graphs showing the relationship between the periodic weighting distance of the main roof and the elastic modulus, thickness and internal friction angle of the immediate roof, the results showed that the periodic weighting distance of the main roof increased with the increase of the thickness or the elastic modulus of the immediate roof and decreased with the increase of the internal friction angle of rock; the thicker the immediate roof, the faster the changing rate of the periodic weighting distance of the main roof; the influence amplitude of a parameter of the immediate roof on the periodic weighting distance of the main roof was affected by other parameters, but the influence trend would not change significantly.%把直接顶视为变形介质,基于老顶、直接顶协调变形机理建立力学分析模型,在给定老顶变形条件下,求解得出老顶周期来压步距与直接顶参数的函数关系式. 对老顶周期来压步距与直接顶弹性模量、厚度以及内摩擦角的关系曲线进行分析,结果显示老顶周期来压步距随直接顶厚度或直接顶弹性模量增大而增大,而随岩石内摩擦角增大而减小;直接顶厚度越大,老顶周期来压步距变化速率越大;直接顶某一参数对老顶周期来压步距的影响幅度会受到其他参数的影响,但其影响趋势不会发生明显变化.
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