针对电气化铁路二线隧道爆破掘进如何确保既有线隧道的安全与行车正常运行的问题，文章介绍了分步开挖方法，从掏槽形式、炮眼分布、炮眼装药结构以及起爆技术等角度回答并很好地解决了这一问题，并在实践应用中取得了很好的技术效果与明显的社会效益与经济效益，为类似工程提供了成功经验。

How to ensure the existing tunnel's safety and the train normal running while the electric railway multiple line tunnel was blast boring? By study and practice,the paper gives an answer through stepped digging method, underholing style, holes scatter and the structure of the hole and detonation technology. It receives good technological achievement and remarkable social and economic benefits in practical application. It provides successful experience for the similar engineering in the future too.