Abstract

In order to solve the directional fracture controlled problem of blasting construction in key parts or specific areas of some projects, two refined directional blasting methods, namely, time sequence controlled (TSC) blasting and notched blasting, are innovatively combined, and numerical comparison research of three kinds of compound blasting methods has been carried out. The results indicate that, for TSC blasting, the optimum delayed denotation time is a certain period of time when the explosive stress wave of the earlier detonated blasthole (EDB) propagates to the wall of the later detonated blasthole (LDB) that away from the EDB. In the TSC-notched blasting with four blastholes as a group, when the LDB and EDB is notched separately, the corresponding directional fracture length is 33.3 d and 45.2 d (d is the blasthole diameter), and the directional fracture length is 52.4 d as the blastholes are all notched. If it is needed to consider both the crack propagation effect and the construction costs, we suggest that the TSC-notched blasting with the notched EDB and the round LDB should be carried out, by which the quality of the profile could be ensured with a low construction cost.

摘要

为解决部分工程重点部位或特定区域爆破施工的定向断裂控制问题，创新性地将时序控制（TSC）爆破和缺口爆破两种精细定向爆破方法相结合，并进行数值对比研究。开展了三种复合爆破方法。结果表明，对于TSC爆破，最佳延迟爆破时间为早爆炮孔（EDB）的爆炸应力波传播到远离EDB的后爆炮孔（LDB）壁的一定时间。 . 在4个炮孔为一组的TSC缺口爆破中，当LDB和EDB分别开缺口时，对应的定向裂缝长度分别为33.3 d和45.2d（d为炮孔直径） ，由于炮孔均为缺口，定向裂缝长度为52.4 d 。如果既要考虑裂纹扩展效果，又要考虑施工成本，建议采用带缺口EDB和圆形LDB的TSC缺口爆破，这样可以保证型材质量，而且成本低。建设成本。