| 摘要 |
PURPOSE: A blasting adjustment method is provided to prevent surrounding rocks from being weak and to obtain a smooth excavated face by exploding a charging gunpowder holder having a groove in parallel with a prearranged excavated line and a hole facing a free face. CONSTITUTION: A charging gunpowder holder (20) contains a lengthwise groove (21) in parallel with a prearranged excavated line (1) and a hole (23) facing a free face. Then, stress concentration occurs in the hole to widen an interval between an outline gunpowder hole (2) and a surrounding gunpowder hole (12). Thus, cracks are prevented from reaching at the charging gunpowder holder inside the outline gunpowder hole. Further, cracks are formed in the direction of the groove and the direction of the hole at the same time so that the opposite direction of the hole has very short cracks for a smooth excavated face. Gunpowder (3) is charged into the charging gunpowder holder before or after the gunpowder holder is inserted into the outline gunpowder holder. After charging the gunpowder, the outline gunpowder hole is tamped using sand or clay and then rock is blasted.
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