Abstract:Based on a shallow buried loess tunnel project of Tongding Expressway, 3D numerical simulation and field monitoring are adopted to study the reinforcement support scheme of the seepage loess tunnel in shallow buried section and analyze the feasibility of reinforcement support of shallow buried section of loess tunnel with advanced pipe shed. The numerical simulation and analysis are conducted for the different reinforcement support measures. The result shows that the settlement of the vault under the advanced pipe shed support is reduced by 16.2%, and the maximum axial force of the initial support is reduced by 19.8%. The monitoring results show that the percentages of vertical displacement reduction (27.8% and 28.1%) between the two methods of advanced pipe shed support and advanced pipe shed + advanced small conduit support are very similar, but the advanced pipe shed support can greatly save the cost and time of extra advanced small conduit application, which effectively control the surrounding rock deformation within the range of vault and verify the economy and effectiveness of advanced pipe shed reinforcement support method.