向家坝水电站右岸横向围堰爆破拆除技术

向家坝水电站右岸坝后横向围堰结构复杂,组分包含素混凝土及碾压混凝土,堰内有廊道,钻孔深度变化较大,且周围环境复杂,爆破振动控制要求高,拆除工期短。为了确保围堰顺利拆除,将其分为水上和水下两类爆破拆除方式,共分5个作业区,对每个作业区炮孔布置、装药结构、装药量、起爆网路等进行了精确的设计,并对每次爆破进行了振动监测,结果表明:单孔药量控制在28kg以内,孔间和排间均采用不同段别的双枚高精度毫秒导爆管雷管连接,实现逐孔起爆,最大爆破振动速度为8.74cm/s,小于允许标准,爆破效果较好。

Explosive demolition technology of transverse cofferdam at right bank in Xiangjiaba hydropower station

The structure of transverse cofferdam at right bank in Xiangjiaba hydropower station is complicated,which is composed of plain concrete and roller compacted concrete,the depth of borehole had great variation.The control requirements for blasting vibration are strict,and the demolition period is short.In order to ensure demolition are smoothly,the transverse cofferdam are divided into two types:dryland blasting and underwater blasting,containing five working areas,the blast hole arrangement,charge structure,detonating network charge are designed accurately,the results show that:single hole charge don't exceed 28 kg,double high precision millisecond detonators of different segments are used among holes and rows,the maximum blasting vibration is 8.74 cm/s,which is less than the allowable standard,and the blasting effect is better.