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采空区顶部岩塊自然陷落时,假顶最小机限合理厚度的确定采空区顶板由于开采的结果,使岩石发生变形,在重力作用下,趋向于自然陷落,突然陷落的岩袭击假顶。作用于假顶的冲击力是很复杂的。因为岩块在重力作用下,对假顶发生撞碰时,是把岩块所具有的位能转变为另一种能——动能形式,这时能量主要地除了使假顶中的松散岩块发生移动和在碰撞瞬间对假顶上部岩块破碎而外,同时以冲击力的方式传递于下部的采空区支架上。为了能计算出当一定大小的岩块袭击着假顶时所产生的冲击力,可以通过多次的模型冲击试验所得到的经验公式近似地计算出冲击力的数值。
Determination of minimum allowable reasonable thickness of roof when natural rock fall in top of gob area The roof of gob roof will deform due to the result of mining and will tend to fall naturally due to the gravity. . Impact on the false roof is very complex. Because the rock mass collides with the roof under gravity, it transforms the potential energy possessed by the rock mass into another energy-kinetic energy form in which the energy is mainly generated except for loose rock mass in the false roof Moving and crushing the rock at the top of the roof at the moment of collision, and at the same time transmitting the impact force to the lower gob support. In order to calculate the impact force generated when rock fragments of a certain size attack the fake roof, the impact force values can be approximated by the empirical formula obtained from multiple model impact tests.