Tunnel construction procedures in a tertiary water-rich fine sandstone stratum with weak muddy cementation

During the early stages, the construction of the Taoshuping tunnel on the Lanzhou-Chongqing railway in a tertiary water-rich fine-sand stratum is very difficult and highly risky because of the softening of surrounding rock that encounters water. In this paper, construction methods and relevant auxiliary measures for this early stage are verified and categorized by establishing procedures on the premise of emphasizing dewatering, increasing pipe density, improving support and matching grouting. Aiming at the tertiary water-rich fine sandstone stratum with weak muddy cementation, this paper focuses on the verification and analysis of procedures like in-tun-nel dewatering, advance support, support structure and radial grouting, providing a practical basis for the design rationality of support parameters for the main tunnel.