INFLUENCE OF NEWLY BUILT TUNNEL OF HIGH-SPEED RAILWAY DEWATERING EXCAVATION ON EXISTING TUNNEL

摘要

The study of the influence of the newly built tunnel construction on existing becomes a popular concerned problem that researchers generally pay close attention to day by day. This paper presents the influence of newly high-speed railway tunnel dewatering construction on the mechanical characteristics of existing municipal tunnel. The study shows that the quantity of ground settlement varies significantly and the differential settlement occurred easily within the range of 50m at dewatering well position; the value of displacement of existing tunnel at infall section is the largest, which decreases gradually with tunnel from medial position to other position and symmetric distribution; the variation and distribution of stress and displacement of lining structure of existing municipal tunnel tends to be uniform. The longitudinal stress in Arch Crown of tunnel is compressive stress and in invert of tunnel is tension stress in range of 30m at infall position, the maximum value of tension stress is 3.09MPa and it is more than the ultimate tensile strength of concrete. Therefore, the influence of dewatering construction is larger. So construction measures must be taken to reduce the impact on the existing municipal tunnel in order to ensure its normal working conditions existing tunnel.