Shallow Tunnel Construction Process Simulation Analysis

In recent years, with the rapid development of the expressway, especially superhighway of our country, highway tunnel in our country have entered the new period of great development, which promotes higher challenge and requestion to build technology of highway tunnel, especially the shallow-depth tunnel in foothill.Based on theoretical method of tunneling construction numerical simulation, the mechanical variety of the surrounding rocks and supporting strcutures in shallow-depth tunnel construction has been studied by plane strain and 3-dimensional elastoplasticity models and the Finite Element Method (FEM). The study was applied to actual projects and got good results.The construction simulation of the three familiar construction processes in actual projects has been performed by plane strain elasticoplastic model with the project of dividing ridge tunnels of Henan Lingnan freeway, and the deformation regulation of its surrounding rocks and supporting has been analyzed. By comparing, the ladder method is suit for constructing the shallow-depth highway runnel, and is accepted by the unit in charge of construction. By comparing with the measured values of the surrounding rocks displacement of the tunnel, the variety regulation of the stress field, displacement field, plastic region of the tunnel's surrounding rocks and the internal force of the supporting in numerical simulation analysis is consistent with the fact. Thus, the numerical analysis can be used in construction guide.Finally, the 3-dimensional FEM numerical emulation analysis program for the shallow-depth highway tunnel has been developed by APDL parametrization design language in ANSYS and can be improved in the future. Construction on dividing ridge tunnel has been simulated to obtain the variety regulation of the stress and displacement of the tunnel's surrounding rocks and the internal force of the supporting, and the effect of biasing carload on stress field of tunnel's surrounding rocks has been simulated too. By comparing with the measured values, the result of numerical emulation is applicable.