乌弄龙水电站地下厂房尾水岩坎围堰拆除爆破

Demolition Blasting of Rock Bar Cofferdam at Tail Water of Underground Powerhouse of Wunonglong Hydropower Station

乌弄龙水电站尾水闸出口岩坎围堰外侧因施工道路占压导致无爆破临空面,围堰内侧距离需保护的建(构)筑物很近,距尾水闸墩混凝土最近距离20m,距尾水检修闸门最近距离30.14m,工况复杂。本文采用高单耗、低单响的爆破设计思路,在围堰下游端15 m长范围爆破形成缺口,剩余围堰段沿围堰轴线方向分段爆破拆除,质点振动速度均控制在允许范围内,爆区周围建(构)筑物完好无损,爆破达到预期效果。

The outer side of the rock bar cofferdam at tail water gate outlet of Wunonglong hydropower station has no free face to carry out blasting due to the pressure of construction road.Besides,the distance from the inner side of the cofferdam to the protected buildings(or structures)is quite close.The nearest distances from the inner side of the cofferdam to pier concrete of tailrace gate and the overhaul gate of tail water are 20m and 30.14m respectively.Due to these factors,the working condition is complicated.In this paper,the design thoughts of high unit consumption and low single shot are adopted for blasting.Blasting is executed within the range of 15m long at the downstream end of cofferdam to form a gap.The remaining section of cofferdam is to be blasted and dismantled by sections along the axis direction of cofferdam.And vibration speed of mass points is controlled within the allowable range.The buildings(or structures)around the blasting area remain intact.Results show that the expected effects of blasting have been achieved.