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He L.,Beijing Jiaotong University | He L.,Capital Group | Wang M.,Beijing Jiaotong University | Li Y.,Beijing Jiaotong University | Li Y.,Beijing Mass Transit Railway Operation Corporation Ltd.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2015

During the urban subway construction, the stages when the tunnel pass under existing pipelines and buildings are always the technology and risk control points. Base on the underground excavated tunnel section of Shen-Zhen subway line5, study was conducted on the influence of concentrated buildings above the excavated tunnels. Tunnel excavation method adopted the up-down-short-terrace method, with temporary Invert and B-pillar. Two calculation conditions are computed by finite element analytical method to determine the optimal excavation strategy, compared to the original condition, the updated calculation condition took Jet grouting pile isolation wall to strengthen soil close to the tunnel structure and dismantled the buildings above the tunnel. The results showed that by the updated calculation condition, the amplitude of ground settlement decrease 49% than the original condition, while the amplitude of settlement on tunnel vault decrease 35%, and amplitude of settlement and differential settlement of adjacent building decrease 67%. Therefore, the treat measure were proved effectively on reducing the influence of ground settlement by excavate construction. ©, 2015, Editorial Office of China Civil Engineering Journal. All right reserved. Source


Xiong S.,Xihua University | Luo J.,Beijing Jiaotong University | Su D.,Beijing Jiaotong University | Li Y.,Beijing Mass Transit Railway Operation Corporation Ltd.
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2016

Combined with three major civil facilities repair cases, which included fire bridges repair, unequal settlement tunnel reinforcement and bridge diseases support replacement on Beijing metro, this paper elaborated the particularity of the civil facilities and the importance of the disease treatment of civil facilities on ensuring the safety operation of Metro. Also it elaborated strict usage control requirements of metro civil facilities, linkage security requirements of every system, and social influence. The emergency safeguard mechanisms and alignment linkage mechanisms in this paper could provide reference for administrative departments at all levels and mass transit railway operation corporations on various regions to formulate relevant mechanisms. © 2016, Editorial Department of Journal of Beijing Jiaotong University. All right reserved. Source


Li Y.,Beijing Jiaotong University | Li Y.,Beijing Mass Transit Railway Operation Corporation Ltd. | Wang M.,Beijing Jiaotong University | Xu H.,Beijing Mass Transit Railway Operation Corporation Ltd. | And 2 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2014

An interval tunnel of Beijing Metro was taken as research background. Based upon the elastoplastic damage constitutive model of concrete and convergence deformation value of tunnel lining structure cross section, the stress, damage and bearing capacity states of tunnel lining structure with crack diseases were studied through analog calculation method. The study shows that, under the practical convergence deformation, the maximum tensile stress of tunnel lining structure is 1.1 MPa, the maximum compressive stress is 9.1 MPa. The arch crown and bottom bear mainly the tensile stress, while the haunch bears mainly the compressive stress. The maximum tensile stress of grid rebar near arch crown is beyond the standard design value of HRB335 rebar. The damage factors of the initial lining and second lining on arch crown and the lining structure on the haunch are all greater than the damage critical values of concrete. The crack diseases on arch crown are mainly caused by the lining structure in tension. The safety factors of inside main rebar, outside main rebar and slant rebar on the arch crown and haunch are all smaller, some reinforcement measures should be taken to deal with the diseases. Source


Qi D.,Beijing Jiaotong University | Liu Y.,Beijing Jiaotong University | Gu Q.,Beijing Mass Transit Railway Operation Corporation Ltd. | Zheng F.,Beijing Mass Transit Railway Operation Corporation Ltd.
Journal of Computers (Taiwan) | Year: 2015

The safety is very important for urban rail transit. So it is the necessary to detect the crack of subway tunnel to keep the secure of the line. In traditional way, relevant staffs are asked to go into the tunnel to detect the crack by naked eye. But this method is too inefficiency to meet the actual demand. In this paper, we propose an algorithm to detect the crack based on the image processing. Compared with other algorithm, this algorithm simplifies the image preprocessing procedure, and use the block binaryzation to replace the traditional method of binaryzation. Then extraneous noisy pixels are removed from the image according to the differences of characteristics between noise and crack. Finally, crack can be detected automatically. Source


Li Y.,Beijing Jiaotong University | Li Y.,Beijing Mass Transit Railway Operation Corporation Ltd. | Wang M.,Beijing Jiaotong University | Xu H.,Beijing Mass Transit Railway Operation Corporation Ltd. | Zhang Y.,Beijing Mass Transit Railway Operation Corporation Ltd.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2014

Since structure diseases associated with tunnel lining are very common for rail tunnel and metro tunnel, reinforcing lining timely is crucial to the safe and long use of tunnel structure. Aiming at the diseases of lining structure of one Beijing subway line, one design work for the destruction test on a prototype model of tunnel lining reinforced by fiber cloth materials is introduced. By using the finite element simulation, comprehensive discusses on the reinforcement effect are carried out from the perspectives of steel stress and lining damage, and the reinforcement form of fiber cloth material for test beam is determined. Results show that adhering 3 layers of 3 m long fiber cloth on the bottom of test beam may achieve the best reinforcement performance. It was found that after the reinforcement, the maximum stress in the grid steel at the vault reduced about 3%, and under each load level, the number of steels in test beam with stress over 300 MPa reduced more than 50%. Analysis the concrete elements with damage factor over 0.7, the number of those elements in the first lining reduced more than 65%, the number of those concrete elements in the second lining reduced 33% under the load of 100kN and the number reduced 11% under the load of 150 kN. Under high stress state, the concrete damage in the second lining was more dispersive, which was beneficial to the structure bearing as a whole. Additionally, adhering fiber cloth inside the experimental beam increased the tensile bearing capacity of the experimental beam. Consequently, the research provides reference design for the future work with fiber cloth reinforcing. Source

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