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Novel SfM-DLT method for metro tunnel 3D reconstruction and Visualization

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Underground Space 2021年第2期6卷 134-141页

作者： Yadong Xue Sen Zhang Mingliang Zhou Hehua Zhu Key Laboratory of Geotechnical and Underground Engineering of Education Ministry Tongji UniversityShanghai 200092China Department of Geotechnical Engineering Tongji UniversityShanghai 200092China

metro tunnels play a crucial role in urban ***,with growing tunnel operation periods,defects,and large deformations appearing,these are influencing tunnel structural performance and threatening public ***-dimensional(3D)tunnel reconstruction is an effective way to highlight tunnel conditions and provide a basis for engineering management and ***,the current methods of tunnel 3D reconstruction do not sufficiently combine the qualitative and quantitative characteristics of tunnel *** this study,a novel method for metro tunnel 3D reconstruction based on structure from motion(SfM)and direct linear transformation(DLT)is *** dimensionless 3D reconstruction point cloud acquired through the SfM method showcases the qualitative characteristics(such as leakage and pipelines)of the tunnel *** close-range photogrammetry DLT method provides scale information missing from the SfM method and quantitative characteristics(such as profile deformation)of the tunnel *** SfM-DLT method was tested in a Shanghai metro tunnel,and proved to be feasible and promising for future tunnel inspections.

关键词： metro tunnel 3D reconstruction Visualization Structure from motion Direct linear transformation

Analytical solution for evaluating deformation response of existing metro tunnel due to excavation of adjacent foundation pit

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Journal of Central South University 2021年第6期28卷 1888-1900页

作者： QIU Ju-tao JIANG Jie ZHOU Xiao-jun ZHANG Yue-feng PAN Ying-dong Key Laboratory of Transportation tunnel Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 610031China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China College of Civil Engineering and Architecture Guangxi UniversityNanning 530004China

The excavation of foundation pit generates soil deformation around existing metro tunnel with shield driving method,which may lead to the deformation of tunnel *** is a challenge to evaluate the deformation of shield tunnel accurately and take measures to reduce the tunnel upward displacement as much as possible for geotechnical engineers.A new simplified analytical method is proposed to predict the longitudinal deformation of existing metro tunnel due to excavation unloading of adjacent foundation pit in this ***,the additional stress of soils under vertical axisymmetric load in layered soil is obtained by using elastic multi-layer ***,the metro tunnel is regarded as a Timoshenko beam supported by Winkler foundation so that the shear effect of tunnels can be taken into *** additional stress acting on the tunnel due to excavation unloading in layered soil are compared with that in homogeneous ***,the effectiveness of the analytical solution is verified via two actual ***,parametric analysis is conducted to investigate the responses of the metro tunnel by considering such factors as the variation of subgrade coefficient,offset distance from the excavation center to tunnel longitudinal axis as well as equivalent shear *** proposed method can be used to provide theoretical basis for similar engineering project.

关键词： metro tunnel simplified analytical method additional stress Timoshenko beam Winkler foundation

Numerical simulation of dynamic response of operating metro tunnel induced by ground explosion

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Journal of Rock Mechanics and Geotechnical Engineering 2010年第4期2卷 373-384页

作者： Yubing Yang Xiongyao Xie Rulu Wang Key Laboratory of Geotechnical Engineering Department of Geotechnical EngineeringTongji UniversityShanghai200092China Shanghai metro Operation Co. Ltd.Shanghai200003China

To evaluate the effects of possible ground explosion on a shallow-buried metro tunnel, this paper attempts to analyze the dynamic responses of the operating metro tunnel in soft soil, using a widely applied explicit dynamic nonlinear finite element software ANSYS/LS-DYNA. The blast induced wave propagation in the soil and the tunnel, and the von Mises effective stress and acceleration of the tunnel lining were presented, and the safety of the tunnel lining was evaluated based on the failure criterion. Besides, the parametric study of the soil was also carried out. The numerical results indicate that the upper part of the tunnel lining cross-section with directions ranging from 0° to 22.5° and horizontal distances 0 to 7 m away from the explosive center are the vulnerable areas, and the metro tunnel might be safe when tunnel depth is more than 7 m and TNT charge on the ground is no more than 500 kg, and the selection of soil parameters should be paid more attentions to conduct a more precise analysis.

关键词： ground surface explosion numerical simulation metro tunnel dynamic response

Mechanical responses of underground carriageway structures due to construction of metro tunnels beneath the existing structure:A case study

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Deep Underground Science and Engineering 2024年第2期3卷 231-246页

作者： Xin Han Fei Ye Xingbo Han Chao Ren Jing Song Ruliang Zhao School of Highway Chang'an UniversityXi'anChina Shandong Province Transportation Planning and Design Institute JinanChina China Water Resources Beifang Investigation Design and Research Co.Ltd.TianjinChina

To understand the mechanical response pattern of the existing structure and ground due to the construction of metro tunnels underneath,the finite difference method is adopted to study the torsional deformation and stress variation of the existing structure and the effect of underground carriageway structures on the surface *** curves of the maximum differential subsidence,torsion angle,and distortion of the cross-section of the existing structure show two peaks in succession during traversing of two metro tunnels beneath *** torsion angle of the existing structure changes when the two tunnels traverse beneath it in opposite *** first traversing of the shield tunnel mainly induces the magnitude variation in torsional deformation of the existing structure,but the second traversing of the subsurface tunnel may cause a dynamic change in the magnitude and form of torsional deformation in the existing *** shielding effect can reduce the surface subsidence caused by metro tunnel excavation to a certain extent,and the development trend of subsidence becomes slower as the excavation continues.

关键词： metro tunnel numerical simulation structural deformation surface subsidence underground carriageway structure

Influence of extreme shallow jacked box tunnelling on underlying metro tunnels:A case study

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Underground Space 2023年第5期12卷 234-250页

作者： Xiaobing Xu Lei Tong Zhuofeng Li Xingwang Liu Qi Hu Hongbo Yao Junyi Li School of Civil Engineering and Architecture Guangxi UniversityNanning 530004China Zhejiang Institute of Architectural Design and Research Hangzhou 310030China Dongtong Geotechnical Technology Co. LtdHangzhou 310000China Hangzhou Xiaoshan Transportation Investment Group Co. LtdHangzhou 311201China

The application of jacked box tunnelling for underground passages has grown rapidly in recent years in *** this study,the design of an extreme shallow jacked box tunnel traversing the underlying metro tunnels was *** innovative additional soil filling above the ground surface was carried out to overcome the overlying-soil-carrying effect of the extreme shallow jacked box *** structural safety of metro tunnels during the jacking process was analyzed through in-situ *** indicated that the overlying-soil-carrying effect was successfully *** metro tunnels generally showed horizontal displacement towards the receiving shaft,uplift and horizontal stretch during the jacking *** stop of jacking machine in front of obstacles generally contributed to the decrease of horizontal displacement,uplift and horizontal stretch of metro *** largest horizontal displacement(1.3–1.6 mm),uplift(1.5 mm)and horizontal convergence(1.6–1.8 mm)generally occurred when the reception of jacking machine was completed,and they all met the requirement of 2 mm for this *** design and construction of this shallow jacked box tunnel project could provide references for future similar projects.

关键词： Box tunnel metro tunnel Soil filling Displacement Convergence

Deformation analysis and safety assessment of existing metro tunnels affected by excavation of a foundation pit

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Underground Space 2021年第4期6卷 421-431页

作者： Shuaihua Ye Zhuangfu Zhao Denqun Wang School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Key Laboratory of Disaster Mitigation in Civil Engineering of Gansu Province Lanzhou University of TechnologyLanzhou 730050China Architectural Design Institute Hefei University of Technology Hefei 230000China

The excavation of a foundation pit considerably affects the adjacent structures and underground pipelines owing to the change in the stress state of the surrounding soil,resulting in *** study of an actual engineering case was conducted to examine the influence of excavation on the deformation of adjacent subway *** finite element analysis software PLAXIS 3D was used to simulate the entire excavation *** structural design of the foundation pit was optimized based on the simulation results to ensure the stability of the foundation pit and the safety of the existing subway tunnel ***,the safety evaluation of the excavation of the foundation pit that caused the deformation of the adjacent subway tunnel was *** influence of the excavation and unloading of the foundation pit on the subway tunnel is closely related to the distance between the subway and the foundation pit,the amount of earthwork excavated at one time,and the engineering geological *** results of this paper can provide useful reference for the design optimization and safety assessment of similar projects.

关键词： Foundation pit excavation Deformation metro tunnel Numerical simulation Safety assessment

Dynamic Risk-Warning of Center Diaphragm and Bench Composite Method During Construction

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Structural Durability & Health Monitoring 2022年第3期16卷 235-254页

作者： Xiaozhong Li Caiyun Sun School of Civil Engineering Lanzhou Jiaotong UniversityLanzhou730070China

During the construction of subway tunnels,safety issues should not be ignored,so it is necessary to prevent and resolve the risk in time and ***,there are some shortcomings in the research of risk assessment,such as the subjectivity of initial data or the lack of scientific evaluation model,in order to solve the problem,this paper relies on the Changping section of the Guanhui Intercity metro,in order to establish a dynamic risk-warn-ing model for the construction process of subway tunnel with the CD-Bench composite ***,a monitor-ing plan was equationted according to the specification requirements and the actual situation of the project,and based on this,an evaluation index system was established from five aspects:geological and support conditions,crown settlement,clearance convergence,and ground settlement and building ***,according to the established risk evaluation standards,the risk level of the index is determined by introducing extension theory and determining the combined weight of the index based on the distance ***,feedback the corresponding risk-warning signals and take control *** the application analysis shows that the model can alarm the risks during the tunnel construction process directly and timely,so the model is feasible and practical,and it is worthy of popularization and application in similar projects.

关键词： Risk-warning monitoring extension theory combination empowerment metro tunnel