The 3D Numerical Simulation and Settlement Control Study for City Tunnel Crossing High Fill Geological Area of Gravelly Soils

Three-dimensional finite element model of tunnel-soil-structures interaction was set up to analyze the causes of settlement and structural cracking when tunnel crossing complex gravelly soil area. It simulated the real tunnel excavation process of Chongqing Metro Line 3. Based on analysis and monitoring results, improved technical measures were used to control settlement, such as advance strengthening, excavation speed control and so on. The latest monitoring results indicate that vault and ground settlement are controlled, and convergence value is reduced significantly. The 3D numerical simulation analysis method provides reference for similar projects, and improvement of technical measures is conducive to settlement control.