Study on Construction Control of Water-Rich Tunnels Based on the Creep Characteristics of Mudstone

Abstract:

To investigate the influence of different supporting parameters and construction methods on the stability of tunnels under the action of surrounding rock creep, a triaxial creep experiment was carried out on soil samples obtained from the site of the Xinjiang water conveyance tunnel project, and the mudstone creep parameters were fitted using the CVISC model. FLAC 3D software was used to build a numerical model based on actual working conditions to optimize supporting parameters. Deformation monitoring after construction control was carried out to verify the validity of the numerical simulation results. The results show that: (1) Mudstone deformation includes instantaneous deformation and creep deformation over time, among which creep deformation is the dominant deformation. (2) Mudstone creep parameters exhibit a high degree of fitting accuracy, and the creep characteristics of mudstone can be characterized by the CVISC model. (3) When the spacing of steel arch frame is 50 cm, the thickness of C25 shotcrete is 25 cm, the length of lock bolt is 4.5 m, and the angle is 60°, tunnel deformation can be effectively reduced and the supporting structure can be fully utilized. (4) The monitoring data after optimizing the construction method on site verified the reliability of the numerical simulation results, proving that the tunnel was stable under the construction control measures and no supporting structure failure occurred.