五强溪水电站扩机工程进水口围堰爆破拆除技术研究  

Blasting Demolition Technology of Cofferdam at Inlet of Expansion Project of Wuqiangxi Hydropower Station

作　　者：文超 李俊 祝文化[2] WEN Chao;LI Jun;ZHU Wen-hua(China Gezhouba Group No.1 Engineering Co.,Ltd.,Yichang 443002,China;School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]中国葛洲坝集团第一有限公司,宜昌443002 [2]武汉理工大学土木工程与建筑学院,武汉430070

出　　处：《爆破》2023年第2期118-123,共6页Blasting

基　　金：国家自然科学基金面上项目(51374163)。

摘　　要：五强溪水电站扩机工程进水口围堰采用预留岩坎+混凝土围堰+土石子围堰的组合结构形式,堰内岩坎为顺层坡,软弱夹层较发育,围堰爆破拆除环境和地质条件复杂。顺层岩坎拆除时无法按常规围堰的经济断面进行大范围削方和一次拆除,深水水下爆破开挖工程量大、块度要求高、施工时间长、安全风险高。爆破拆除过程中在保证围堰稳定的条件下,采取垂向分层、水平向分区、台阶松动爆破的施工方法,尽可能多地实施陆上开挖。水下爆破根据岩坎地质条件、岩体力学特性及覆盖水深(20~37 m),结合水下爆破清渣块度要求,采用0.9~1.1 kg/m^(3)的炸药单耗。通过数码电子雷管高精度延时起爆技术,严格控制单段最大药量(60 kg以内),并设置气泡帷幕和柔性防护网等一系列安全防护措施。经现场爆破监测结果表明:爆破振动及水击波对进水口闸门等建构筑物的影响得到了有效控制,提高了水下清渣、转运效率得到了提高。The inlet cofferdam of the expansion engineering of Wuqiangxi hydropower station consists of the reserved rock barrier,concrete,soil and stones.The rock barrier is a bedding slope with relatively developed soft interlayers,which results in a complicated geological condition and blasting demolition environment for the cofferdam.In the process of demolishing the bedding rock barrier,it is impossible to break the rock once in a large area according to the economic section of a conventional cofferdam due to the large engineering quantity of the underwater blasting excavation,high requirement of fragmentation,long construction time and high risk.Under the condition of ensuring the stability of the cofferdam,the method of vertical stratification,horizontal zoning and loosening bench blasting was adopted to implement land excavation as much as possible.For the underwater blasting,according to the geological conditions of rock barrier,the mechanical characteristics of rock mass,the water depth(20~37 m)and the fragmentation requirement,the powder factor of 0.9~1.1 kg/m^(3) and maximum charge per delay of 60 kg was adopted.Electronic detonators were used for blast hole initiation and a series of safety measures such as bubble curtains and flexible protective nets were set.The field monitoring results show that the effect of blasting vibration and water percussive wave on structures such as inlet gate has been effectively controlled,and the efficiency of underwater slag removal and transfer has been improved.

关 键 词：扩机工程 进水口 围堰拆除 岩坎 顺层坡 

分 类 号：TD235.3[矿业工程—矿井建设]