Abstract：
The exit of the Xinnanling tunnel of the Wuhan-Guangzhou passenger-dedicated rail line passes through a karst area full of clay and fragmented stone that measures more than two hundred meters. Pre-reinforcement and advance support methods are time-consuming and usually result in construction delays and economic losses. In order to guarantee the construction schedule and quality, a circuitous drift heading was adopted, which allowed for geological forecasting and multi-face construction for the section characterized by adverse geological conditions. This paper describes the general planning, implementation, and effects of circuitous drift heading in terms of mud gushing, surface subsidence, and detection of karst full of clay and rubble at the tunnel exit.
2013, Vol. 50 