The Experts below are selected from a list of 1416 Experts worldwide ranked by ideXlab platform
Lulu Zhang - One of the best experts on this subject based on the ideXlab platform.
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three dimensional numerical modeling of a deep excavation adjacent to shanghai Metro Tunnels
International Conference on Conceptual Structures, 2007Co-Authors: Y M Hou, Jiqiu Wang, Lulu ZhangAbstract:Due to rapid construction and limited urban area in Shanghai, some deep excavations are very close to the existing Metro Tunnels or sensitive superstructures. Therefore the safety of the adjacent Tunnels and surrounding structures become an important issue during design and construction of these deep excavations. This paper presents a 3D finite-element modeling using the finite element analysis program ABAQUS for an oversize deep excavation in Shanghai soft deposits. The excavation is the excavation of the north square underground shopping center of Shanghai South Railway Station. Two cases of numerical analyses assuming anisotropic and isotropic soil stiffness respectively are conducted. The estimated wall deflection and ground movements are compared with the field monitoring results. It is found that soil stiffness anisotropy has a significant effect on the accuracy of prediction of the diaphragm wall deflection and the ground movement around excavation for the oversize excavation in Shanghai soft deposits. The calculated ground movements of the anisotropic case agree well with the field measurements.
Wei Huang - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of dynamic response law of intersecting Metro Tunnels in upper and lower strata
Geotechnical and Geological Engineering, 2020Co-Authors: Wei HuangAbstract:With the acceleration of urbanization process, more and more urban subway construction, inevitably space intersection of subway Tunnels has been formed. Based on practical engineering cases, a three-dimensional model is established by using MIDAS-GTS/NX numerical software. The dynamic response of Metro tunnel under seismic wave is analyzed. The effect of tunnel intersection angle on the dynamic response law is discussed. The results show that: (1) Acceleration amplification factor, internal force and displacement of intersecting Tunnels increase first and then decrease along the measuring points. The dynamic response of the area where the upper and lower Tunnels intersect is the strongest. (2) The dynamic response of the tunnel in the upper soil is stronger than that in the lower rock. The difference of dynamic response between two Tunnels in the same stratum is small. (3) With the increase of the intersection angle between the upper and lower Tunnels, the acceleration and shear force decrease gradually. There is a negative correlation. The exponential function is established to describe the functional relationship between the dynamic response and the angle. The research results can provide references for earthquake resistance and shock absorption of urban Metro.
Wangping Qian - One of the best experts on this subject based on the ideXlab platform.
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evaluation of structural fatigue properties of Metro tunnel by model test under dynamic load of high speed railway
Tunnelling and Underground Space Technology, 2019Co-Authors: Wangping Qian, Xiao Liang, Zhiyi Jin, Bo LeiAbstract:Abstract As the acceleration of urbanization and modernization process in China, there will be more and more cross-projects between Metros and high-speed railways and other projects. For near distance cross-projects, the structural fatigue problems caused by dynamic loads of high-speed trains are also becoming increasingly serious in tunnel engineering. A large-scale model test was utilized to study structural fatigue problems of shield Tunnels under high-speed railway dynamic loads. Firstly, based on a large number of numerical simulations, the complex dynamic load of high-speed railway was simplified to a simple sinusoidal wave, and the most unfavorable position of segmental linings was proposed. Then, the fatigue assessment method of segmental linings in the prototype and cyclic load times in the laboratory were also put forward. Finally, in the model test, some key technical details were also analyzed, including the types of segmental linings, similarity principle and materials, sensors layout, and model fabrication. The results illustrate that the simplified waveform is well applied to numerical simulation and model experiment under the action of a single load. The experiment reveals that there are no obvious fatigue cracks and structural failure during the whole loading process, and the research draws the conclusion that the fatigue life of Metro shield Tunnels can meet the requirements of the service life of 120 years. Furthermore, there is an important phenomenon of the uplift and dislocation of segmental linings in a certain range. Therefore, the research results can also provide a good guidance for the design of a new Metro tunnel and the repair and maintenance of built Metro Tunnels.
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deformation characteristics and safety assessment of a high speed railway induced by undercutting Metro tunnel excavation
Journal of rock mechanics and geotechnical engineering, 2019Co-Authors: Wangping Qian, Taiyue Qi, Yunjian Zhao, Yizhou Le, Haiyang YiAbstract:Abstract Stratum deformation (settlement) is a challenging issue in tunnel engineering, especially when construction of Metro Tunnels has to undercut high-speed railway. For this purpose, we used the FLAC3D software to analyze the stratum settlement characteristics of high-speed railway at different crossing angles intersected by Metro tunnel, in terms of ground settlement trough, stratum slip line and irregularity of ballastless tracks. According to the evolution of the stratum settlement at different angle regions, an optimized angle is proposed for the actual project design. In order to reduce the influence of stratum settlement on the safety of high-speed railway, an approach of safety assessment is proposed for the shield engineering undercutting high-speed railway, as per Chinese specifications using numerical results and on-site conditions. A case study is conducted for the shield tunnel section crossing the Wuhan – Guangzhou High-speed Railway between the Guangzhou North Railway Station and the Huacheng Road Station, which represents the first Metro tunnel project passing below a high-speed railway in China. A series of measures is taken to ensure the safe excavation of the shield tunnel and the operation of the high-speed railway. The results can provide a technical support for performing a safety evaluation between high-speed railways and Metro Tunnels.
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Deformation characteristics and safety assessment of a high-speed railway induced by undercutting Metro tunnel excavation
Elsevier, 2019Co-Authors: Wangping Qian, Yunjian ZhaoAbstract:Stratum deformation (settlement) is a challenging issue in tunnel engineering, especially when construction of Metro Tunnels has to undercut high-speed railway. For this purpose, we used the FLAC3D software to analyze the stratum settlement characteristics of high-speed railway at different crossing angles intersected by Metro tunnel, in terms of ground settlement trough, stratum slip line and irregularity of ballastless tracks. According to the evolution of the stratum settlement at different angle regions, an optimized angle is proposed for the actual project design. In order to reduce the influence of stratum settlement on the safety of high-speed railway, an approach of safety assessment is proposed for the shield engineering undercutting high-speed railway, as per Chinese specifications using numerical results and on-site conditions. A case study is conducted for the shield tunnel section crossing the Wuhan – Guangzhou High-speed Railway between the Guangzhou North Railway Station and the Huacheng Road Station, which represents the first Metro tunnel project passing below a high-speed railway in China. A series of measures is taken to ensure the safe excavation of the shield tunnel and the operation of the high-speed railway. The results can provide a technical support for performing a safety evaluation between high-speed railways and Metro Tunnels. Keywords: Metro tunnel excavation, High-speed railway, Settlement characteristics, Safety assessment, Numerical simulation, Case applicatio
Y M Hou - One of the best experts on this subject based on the ideXlab platform.
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three dimensional numerical modeling of a deep excavation adjacent to shanghai Metro Tunnels
International Conference on Conceptual Structures, 2007Co-Authors: Y M Hou, Jiqiu Wang, Lulu ZhangAbstract:Due to rapid construction and limited urban area in Shanghai, some deep excavations are very close to the existing Metro Tunnels or sensitive superstructures. Therefore the safety of the adjacent Tunnels and surrounding structures become an important issue during design and construction of these deep excavations. This paper presents a 3D finite-element modeling using the finite element analysis program ABAQUS for an oversize deep excavation in Shanghai soft deposits. The excavation is the excavation of the north square underground shopping center of Shanghai South Railway Station. Two cases of numerical analyses assuming anisotropic and isotropic soil stiffness respectively are conducted. The estimated wall deflection and ground movements are compared with the field monitoring results. It is found that soil stiffness anisotropy has a significant effect on the accuracy of prediction of the diaphragm wall deflection and the ground movement around excavation for the oversize excavation in Shanghai soft deposits. The calculated ground movements of the anisotropic case agree well with the field measurements.
Wang Weidong - One of the best experts on this subject based on the ideXlab platform.
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two stage method for analyzing effects on adjacent Metro Tunnels due to foundation pit excavation
Rock and Soil Mechanics, 2011Co-Authors: Wang WeidongAbstract:Unloading of foundation pit excavation will no doubt induce the soil deformation and have result in uneven settlements of adjacent Metro Tunnels.The excessive settlements may induce the crack of tunnel segments and eventually may affect the safety use of Metro trains.Two-stage method is presented for determining the longitudinal deformation of Metro Tunnels caused by adjacent foundation pit excavation.The soil unloading effects of the bottom plan and the surrounding walls induced by the foundation pit excavation can be considered by this method.Firstly the additional stress due to adjacent foundation pit excavation is calculated.Secondly the governing differential equation is built up based on Winkler model.Then the differential equation is deduced to the finite element equation by the Galerkin method;and vertical displacement and internal forces along longitudinal axis are obtained.Furthermore,the parametric analysis of existing Tunnels is carried out;such as,the different depths,the distance from the excavation site,the different geologic conditions and the different outer diameter of the tunnel.Finally,the results from present approach are compared with that from 3D numerical simulation and measured data;good agreement is obtained.It may provide certain basis to draw up correctly protective measures of Metro Tunnels influenced by adjacent excavation.
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numerical modeling analysis on deformation effect of Metro Tunnels due to adjacent excavation of foundation pit
Journal of Wuhan University of Technology, 2007Co-Authors: Wang WeidongAbstract:Unloading of excavation of foundation pit will no doubt have influence on adjacent Tunnels.Therefore it is important to predict the deformation of Metro Tunnels and propose the corresponding preventive and protective measurements.According to the project of deep excavations neighboring the tunnel in Shanghai,the elastoplastic analysis on deformation effect of Metro Tunnels due to adjacent excavation of foundation pit is carried out with integral finite element method.The results show good agreement with the field test data,it is showed that the integral finite element method can provide good simulation for this kind of engineering activity and provide convincing computing results for the design and construction.