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通过对大量实测资料进行数理统计分析,找出了直接顶初次垮落步距l和岩石单向抗压强度σ、节理裂隙间距I和分层厚度h的经验方程l=-1.58+6.21h+0.019σ+8.93I。提出了用岩体强度指数D将直接顶分类,并用直接顶厚度和采高的比值N以及老顶初次来压步距L将老顶分级的方案。同时相应地提出了各级类顶板使用液压支架或单体支柱时的架型、支护强度和顶板管理方法。
Through the mathematical statistics analysis of a large number of measured data, the empirical equation l = -1.58 + 6.21h + of direct roof first caving step and rock unidirectional compressive strength σ, joint fissure spacing I and delamination thickness h were found. 0.019σ + 8.93I. A direct top classification method based on rock mass strength index D is proposed, and the scheme of grading the old roof by using the ratio of direct roof thickness to mining height N and the initial pressure step L of the old roof is proposed. At the same time, correspondingly, the frame type, supporting strength and roof management method when using hydraulic supports or single supports at all kinds of roofs are put forward.