1·There is a certain angle between caving line and coal seam strike.
垮落线与煤层走向是一定角度。
2·Finally, the distribution law of stress filed and the causes of goaf caving zone were analyzed according to the primary stress nephogram.
最后从主应力云图来分析了采空区内部的应力场分布规律及空区垮落带形成的原因。
3·The false top is the existence pole exchanges weak caving rock stratum between the coal seam and direct top. In the coal mining, it may often be happened.
伪顶是在煤层与直接顶之间存在的极易垮落的软弱岩层，在井下采煤工作面回采时，会常常遇到。
4·Caving angles of roofs among key strata are different because of the differences of the load-bearing effect of key strata and mechanical characters of rock strata.
关键层的承载作用和岩层力学特性的差异使关键层间顶板的垮落角不同。
5·The deformation characters of the broken rocks are the important factors that affect the roof caving and surface subsidence above goaf in coal mining.
破碎岩石的变形性质是影响采空区覆岩垮落与地表沉陷的重要因素。
1·We also introduced statistical way to analyze the strata in the initial roof caving and carried out reasonable classification.
采用统计学的方法进行了矿压分析和总结，根据初次放顶顶板情况进行了合理分类。
2·Because the first caving of work face haven't been finished, the tunnel roof and hole can not be used and gas often goes beyond the limit, so some measures must be taken.
由于工作面初次放顶没有完成，顶板巷道、顶板钻孔等不能发挥作用，常发生瓦斯超限现象，必须采取针对性措施。