Abstract: A completely emptying of Baiyun reservoir is required for dam leakage treatment, which needs to open up the original construction diversion tunnel. In addition to the inlet gate, the diversion tunnel also includes a temporary concrete plug with 6 meters in length and an permanent plug with 26 meters in length. Only by removal of the temporary plug and permanent plug and lifting the underwater gate can the water be released. According to the construction plan, the first step is to demolish permanent plug by blasting, lift the inlet gate, and then carry out explosive demolition of temporary plug in one shot. By research, the generation of advanced tunnel by explosive demolition is accepted, which is successfully applied and good results are achieved.

Key words: concrete plug, underwater rock plug blasting, advanced tunnel

摘要： 湖南城步白云水库大坝渗漏治理工程需要彻底放空水库，而放空水库必须打通原施工导流洞。导流洞除了进口闸门外还设有6 m长混凝土临时堵头和26 m长永久堵头，需要拆除永久堵头和临时堵头，并提起导流洞进口水下闸门后才能顺利泄水。施工方案为先爆破拆除永久堵头，然后提起导流洞进口闸门，最后一次性爆破拆除6 m长临时堵头（挡水水头约有47 m）实现贯通。通过多方研讨，最终采用爆破形成先导洞的方式进行临时堵头一次性爆破拆除，此方案成功应用并取得了良好的效果。

关键词: 混凝土堵头, 水下岩塞爆破, 先导洞