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针对在厚层直接顶条件下的沿空留巷工程,建立了顶板破断的力学模型;结合材料力学,对顶板断裂位置可能性进行了分析,并通过计算得出顶板断裂位置;顶板破断后形成“斜跨梁”式的承载结构,给出顶板破断后岩块下沉量的计算公式,在此基础之上,分析了相邻岩块对顶板破断结构的水平挤压作用,得出在厚层直接顶条件下顶板更容易形成稳定的承载结构;提出了“临界厚采比”作为厚层直接顶条件的评判标准并推导了其计算公式。
Aimed at the gob-side entry retaining project under thick direct top conditions, the mechanics model of roof breaking is established. According to the mechanics of materials, the possibility of roof breaking position is analyzed and the roof breaking position is calculated. This paper gives the formula of the subsidence of the rock mass after the roof is broken, and on this basis, analyzes the horizontal squeezing action of the adjacent rock mass on the roof broken structure, In the case of thick direct roof, the roof is easier to form a stable bearing structure. The criterion of “critical thick coal ratio” is proposed as the criterion of thick direct roof condition and its calculation formula is deduced.