Abstract:

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.

Key words: waterreleasing tunnel, blasting construction, tunnel lining, influence analysis