Abstract Directional roof-cutting with shaped charge blasting is dangerous and produces large vibrations. Accordingly, a new, nonexplosive method known as instantaneous expansion with a single fracture (IESF) has been developed and tested in the field. This method uses a slit-oriented pipe and a special slitting agent triggered by electric current without a detonator. It is capable of producing a single crack that propagates through the rock in a selected direction. The mechanism of directional roof-cutting using IESF is analyzed, and the conditions for directional crack initiation and propagation are presented. The new technique has been successfully applied to directional roof-cutting in an actual coal mine. It resulted in a larger crack rate, a smaller charge, reduced vibration, and an improved safety profile than shaped charge blasting. IESFs are a substitute for explosives and are expected to have broad application prospects in directional rock breaking.

中文翻译：

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一次断裂瞬间膨胀：一种用于顶板切割的定向破岩新技术

摘要 聚能装药爆破定向切顶危险且振动大。因此，已经开发并在现场测试了一种新的非爆炸方法，称为单裂缝瞬时膨胀 (IESF)。该方法使用狭缝定向管和特殊的切割剂，由电流触发，无需雷管。它能够产生沿选定方向在岩石中传播的单个裂缝。分析了使用 IESF 定向切割屋顶的机理，并给出了定向裂纹萌生和扩展的条件。该新技术已成功应用于某实际煤矿的定向顶板切割。与聚能装药爆破相比，它导致更高的破裂率、更小的装药量、减少的振动和更高的安全性。