This article makes introduction from several aspects, e. g. bulk factor control, effective environment excavation, and window & wall area ratio control etc. 文章從控制體型系數(shù)，有效挖掘環(huán)境及控制窗墻面積比等方面進(jìn)行了論述。
During the initial excavation, the tender coal seam workings in deep seam in Nantun Colliery takes on slocking of roof, with breaking-out in bulk coal and surrounding rock failure. 南屯煤礦深部松軟煤層巷道，在掘進(jìn)過(guò)程中頂板破碎，伴有大量頂煤冒落且圍巖破壞嚴(yán)重。