Construction of a railway tunnel in water-rich tertiary sandstone

The Cheng-er-shan tunnel is mainly located in water -rich tertiary sandstone, and plastic flow deformation could occur if the rockmass is disturbed due to poor stability. In this paper, the nature of tertiary sandstone, and the pros and cons of the construction methods adopted in the early stage are analyzed and summarized; a concept of dominant dewatering, supplementary grouting, heavy support, and rapid sealing is raised in terms of the design and construction; and such construction measures as advance dewatering, advance pre-support, double-layer primary support, and secondary lining are described in detail. ©, 2015, Editorial Office of Modern Tunnelling Technology. All right reserved.