某铁路隧道建成运营后，受溶洞区域水压大的影响，岩溶核心段出现衬砌渗漏水现象。为了解决衬砌渗漏水问题，通过在正洞顶部施作引水洞，截取岩溶水，减小作用在隧道衬砌周围的荷载。本文结合某铁路隧道引水洞爆破施工，通过从爆破震动、结构变形等动态监控和土压力、型钢应力、混凝土应变等静态监控，分析引水洞施工期间正洞衬砌结构受力和变形情况，得出爆破震动速度和结构受力都控制在允许标准以内，并且隧道结构变形很小、结构受力相对稳定，说明引水洞施工对正洞衬砌结构影响小，保证了运营线的安全。

Due to the high water pressure in the karst cave area, water seepage occurs to a railway tunnel after it has been put into operation. Two waterreleasing tunnels are excavated on top of the mentioned railway tunnel to intercept the karst water and to reduce the load on the tunnel lining, so as to solve the water seepage problem. In the paper, the blasting construction of the waterreleasing tunnel is presented, the loading on and deformation of the main railway tunnel during the construction of the waterreleasing tunnel are analyzed on basis of the results of the monitoring of the blasting vibration, the structural deformation, the surrounding rock pressure, the stress on the shapedsteel arches and the strain of the concrete lining. The analysis shows that both the blasting vibration velocity and the stress on the main railway tunnel structure are within the allowed standard, the deformation of the main railway tunnel structure is small and the loading on the main railway tunnel structure is relatively stable. It is concluded that the influence of the blasting construction of the waterreleasing tunnel on the main railway tunnel is small and the normal operation of the railway line can be guaranteed.