人防设施发生的断裂、陷漏、塌方和大面积渗水；
The accident that the facilities of people's air defense happen, because of rupturing, falling into the reason to leak, cave in and infiltrate by a large scale
基于相似材料模拟实验与现场矿压观测，本文分析了大面积剥离顶板的断裂与运动特点。
Based on a number of experiments on equivalent materials and field observation, the break and moving features of separative roof in a large area has been analyzed.
大面积的餐台玉石面，必须竖抬，避免餐台断裂。小面积的玉石面也应竖拿，切忌平面横抬横拿。
The large bowlder surface of dinner table must be uplifted vertically in avoidance of breakage. The small one shall also be held vertically instead of horizontally.
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