导流隧洞进口堰前引渠水下爆破施工技术

小湾水电站导流隧洞进口围堰外引渠水下爆破开挖，采用了目前国内较为先进的孔内延时、孔外微差的爆破技术，整个爆破区分为多段起爆，从而达到高单耗，低单响药量的控制目的，将质点的最大振动速度控制在允许范围内，有效保证了围堰、围堰岩埂灌浆帷幕区及进水塔等建筑物的安全，为导流隧洞顺利导流提供了保证。

Underwater blasting execution technique of approach channel in front of weir of the inlet of diversion tunnel

A new advanced blasting technique in China, delay in hole and sequence out hole blasting technique, was adopted in underwater blasting excavation of approach channel of diversion tunnel of Xiaowan Hydropower Station, thereby the controlling aim of high explosive rate and low single dynamite weight was achieved, the maximal particle vibration velocity was controlled in allowable range, guaranteed the safety of cofferdam and rock dam and entrance water tower and so on, provided powerful guarantee for the successful guide water of the guide tunnel.