控制爆破在三峡上游围堰防渗墙拆除中的应用

Application of controlled blasting technology in removal of cut-off wall at TGP's upstream cofferdam

三峡工程二期上游围堰混凝土防渗墙拆除爆破 ,采用不耦合、间隔装药结构 ,孔间微差、非电接力复式交叉起爆网络方案 ,于 2 0 0 2年 5月 1日一次爆破成功。爆破孔数 5 41个 ,总装药量约 16t,最大单段起爆药量 3 3 .6kg ,爆破总延期时间 173 88ms。爆破引起的振动速度值远小于设计标准 ,宏观调查效果良好 ,达到了预期目标。

The concrete cut off wall of the upstream cofferdam for construction of the Three Gorges Project's stage Ⅱ works was removed by blasting. The blasting was successfully carried out on May 1, 2002, using an uncoupled intermittent charging structure and an alternate initiation network of differential nonelectric servo mechanism. 541 blastholes and 16 t of blasting cartridges were used in this blasting. The maximum single-section amount of blasting cartridges was 33.6 kg and the total blasting delay-time was 17 388 ms. The observed vibration velocities caused by the blasting were much smaller than those stipulated in design standards and the results from a macro investigation were excellent, achieving the expected objective.