Analysis of the deformation induced by the advance pre-reinforcement construction of a large cross-section tunnel in water-rich sandy rock

As for the engineering characteristics of sandy rock, advance pre-reinforcement with horizontal jet grouting was applied in the large cross section of the Taoshuping Tunnel on the Lanzhou-Chongqing Railway. This paper presents a detailed analysis of the extrusion deformation, pre-displacement, crown settlement, and convergence that was carried out by finite element numerical simulation and theoretical calculations combined with field monitoring data. The analysis shows: 1) the initial maximum displacement rate is in direct proportion to the final accumulative displacements; 2) Crown settlement and convergence displacement present obvious spatial effects; and 3) Crown settlement and convergence displacement have certain relevance.