城市拆除控制爆破中的飞石控制

根据长期现场工程实践总结出，在城市拆除控制爆破中，引发飞石的主要原因是：对被爆介质的性质和结构特点了解不够，炮眼的布置和钻眼的方向，最小抵抗线的位置和大小，炸药单耗的高低，装药结构形式等爆破参数选择不当，施工质量未达到要求，覆盖位置不对或覆盖厚度不够等，针对于此，提出防治爆破飞石的有效技术措施有：熟悉被爆体的力学性能和结构特点，正确选定最小抵抗线的位置和方向，微分装药并严格控制装药量和选择合理的装药结构，保证正确顺序起爆，精确钻眼和施爆，加强覆盖防护，此外，文中还介绍了几种爆破飞石抛掷距离的估算方法。

Effective technique of controlling fly-rock in demolition blasting in city

Based on the long term engineering practices of demolition controlling blasting in city, the principal causes of fly-rock made by blasting are generalized, namely: the property and structural feature of blasted medium are understood insufficiently; the blasting parameters, such as hole placing and holing, the burden position and its length, the explosive ration and charging construction forms are selected incorrectly; the construction equality can not be attained , and covering position is incorrect or covering thickness is insufficient. On these accounts, the effective techniques of controlling fly-rock are put forward. Namely, the techniques are that the properties mechanics and the structural features of blasted medium should be understood sufficiently; the burden position and its direction should be selected correctly; the chare quantity should be controlled with differential charge and charge structure should be chosen rationally; the blasting pattern should be correct; the holing and blasting should be accurate; and the covering protection should be strengthened. In addition, several estimate methods of casting distance of blasting fly-rock are introduced in this paper.