关键词: 盾构隧道, 多线叠交, 模型试验, 数值模拟, 岩体变形

Abstract: Multi-line overlapping shield tunnel has a complex form in underground space layout. The interaction mechanism between tunnels and soil is very complex. The new tunnel caused ground settlement and made adverse effects when traversing the existing tunnels. The drainage method model test was applied according to the technical requirements of shield tunneling and control requirements of approaching construction. The ground surface subsidence and the existing tunnels longitudinal deformation caused by strata damage and excavation unloading are analyzed for three typical construction methods, above-crossing, under-crossing and above-under crossing. Finite element model was built to simulate the dynamic construction process of model test. The results show that ground settlement turns to be larger, and the existing tunnels have an upward moving during the construction of up-crossing. While under-crossed, a smaller settlement with a tendency of subsidence is found in the existing tunnel. The under-crossing first and then above-crossing construction leads to a uniform variation in ground settlement during various construction stages, and the final settlement is relatively small. The above-crossing first and then under-crossing construction results in a great curvature in deformation curve of existing tunnel, and the deformation of existing tunnel fluctuates constantly. The research results can provide some theoretical basis and prophase guidance for similar projects in the future.

Key words: shield tunneling, multi-line overlapped, model test, numerical simulation, geotechnical deformation