坑内矿山在回采矿房储量的过程中形成了空区,而这些空区是用矿房之间和中段之间的矿柱来支撑的。由于继续回采,形成的空区也逐渐扩大,就会造成继续回采的困难,也无法回收矿柱。当空区扩大到应力集中系数超过矿柱强度的允许值时,矿柱就自行崩落,使上盘突然塌陷,造成坑内事故。 The pit mines formed empty areas during the recovery of the reserves of the mines, which were supported by the pillars between and between the mines. As a result of continued mining, the empty space formed will also gradually expand, which will cause difficulties in continuing mining and will not be able to recover pillars. When the area expanded to stress concentration coefficient exceeds the allowable value of the strength of the pillars, the pillars collapse on their own, so that the plate suddenly collapse, resulting in pit accidents.