Due to a drainage problem, the Lanzhou to Chongqing high-speed rail line had been out of service during the 2015 wet season, so a drainage tunnel was to be constructed for the line and was required to be accomplished before the 2016 wet season. This drainage tunnel is only 5 meters below the line which is in service, therefore blasting vibration needs to be strictly controlled. This article introduces all the applied blasting methods, parameters and detonation throughout the entire project, finally bringing in the electronic detonator stagger phase technique and corresponding time difference for detonation.The construction site had complicated geology with hard rock. The trial blasting results showed the peak particle velocity and basic frequency of blasting waves were far larger than the results in similar projects. Conventional methods will be ineffectual for reducing blasting vibration, and the hole by hole method with electronic detonators cannot always have apparent effect, consequently, the stagger phase method with electronic detonators was adopted.Construction results exhibit the prominent blasting effect by using the stagger phase method, blasting vibration is effectively controlled. This enabled the drainage tunnel to be completed before the wet season; hence high-speed rail is prevented from being out of service. This article can be a sound reference to similar engineering projects.
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