通过采用含空孔的直孔掏槽方式、反向起爆，并合理选择微差起爆时间，桩井爆破的平均炮孔利用率达到了90 %。
Through adopting the parallel cut and inverse initiation, and selecting correct delay-interval, an average blasting efficiency of 90% had been achieved.
文中通过一个成功的工程实例，初步探讨和总结了用爆破施工法拔出深井井管的方法、原理以及注意事项。
Through a successful Engineering example, this paper discussed and summarized the method, principle and attentive items for drawing out deep-well tubes by the construction technique of blasting.
许楼煤矿在主井人工冻结巨厚砾岩段施工中，采用了控制爆破技术。
A controlled blasting technology was applied to the construction of freezing thick gravel stratum section in the main shaft of Xulou Mine.
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