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Deformation Law of a Metro Tunnel underneath an Existing Urban Road in Combination Soft/Hard Stratum
(1 School of Civil Engineering, Shandong University, Jinan 250061; 2 Jinan Municipal Engineering Design & Research Institute(Group) Co. Ltd., Jinan 250101; 3 Geotechnical and Structural Engineering Research Institute, Shandong University, Jinan 250061)
Abstract Large surface settlement is often caused by tunnel construction in a stratum with a soft upper part and hard lower part, and this endangers any existing buildings. Based on the Antuo-Mountain Entrance/Exit Line project of Shenzhen subway line 7 underneath the North Ring Road, a numerical calculation model is set up by three-dimensional finite differential software FLAC3D under combination of numerical simulation and field monitoring to analyze the characteristics of ground surface settlement and stratum settlement during construction of the V-shaped tunnel underneath the existing road, and a comparison and demonstration is conducted by field monitoring and measurement. The results show: 1) the ground settlement trough mainly presents in a Y shape; 2) the superposed effect of the crown settlement trough is obvious when the interval of two tunnels is less than 2.0D, and the superposition of ground surface settlement increases greatly when the interval of two tunnels is less than 4.0D; and 3) the influential scope of overlying ground deformation decreases with an increase of the depth. The effect of advanced support on ground surface settlement is described and a comparative study of the parameters for advanced grouting is conducted so that the construction method and support measures are optimized.
Abstract：
Large surface settlement is often caused by tunnel construction in a stratum with a soft upper part and hard lower part, and this endangers any existing buildings. Based on the Antuo-Mountain Entrance/Exit Line project of Shenzhen subway line 7 underneath the North Ring Road, a numerical calculation model is set up by three-dimensional finite differential software FLAC3D under combination of numerical simulation and field monitoring to analyze the characteristics of ground surface settlement and stratum settlement during construction of the V-shaped tunnel underneath the existing road, and a comparison and demonstration is conducted by field monitoring and measurement. The results show: 1) the ground settlement trough mainly presents in a Y shape; 2) the superposed effect of the crown settlement trough is obvious when the interval of two tunnels is less than 2.0D, and the superposition of ground surface settlement increases greatly when the interval of two tunnels is less than 4.0D; and 3) the influential scope of overlying ground deformation decreases with an increase of the depth. The effect of advanced support on ground surface settlement is described and a comparative study of the parameters for advanced grouting is conducted so that the construction method and support measures are optimized.
.Deformation Law of a Metro Tunnel underneath an Existing Urban Road in Combination Soft/Hard Stratum[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(6): 126-135
2017, Vol. 54 