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Hu S.-M.,Beijing Urban Construction Design & Development Group Co.
Tiedao Xuebao/Journal of the China Railway Society | Year: 2015

With regional tunnel in Xi'an metro as the project background, by means of theoretical analysis, site experiment and finite element numerical calculation, the safety for support parameters was evaluated based on convergence-confinement method. The results showed that: (1) The characteristic curve of the loess stratum can be divided into straight line and curve segments. Yield first occurred at sidewall surrounding the tunnel and plastic slip wedge gradually formed extending to the vaults and arch bottom; (2) All the components in the composite support structure were in parallel to bear the pressure of surrounding rock; (3) The mechanical properties of supporting structure in a plastic state were deteriorated sharply. As plastic yield was not allowed in the supporting structure during the construction and operation, this paper proposed the method of defining the safety factor of supporting structure from the perspective of allowed displacement; (4) The maximum reaction force that the supporting structure provided during the field test was greater than the stress of the equilibrium point between surrounding rock and supporting characteristic curve, showing that current supporting parameters met the safety requirements; (5) The safety evaluation method for supporting structure was proposed from the perspective of the permissible displacements. Through the finite element calculation results, the corresponding strata and support characteristic curves were drawn to obtain corresponding safety factors. The calculation showed that the minimum safety factor of the tunnel support structure was 1.14 at the sidewall, which should receive attention during design and construction. ©, 2015, Science Press. All right reserved.

Li Z.,Beijing Jiaotong University | Wang C.,Beijing Urban Construction Design & Development Group Co. | Su H.,Beijing Jiaotong University | Shi S.,Beijing Jiaotong University | Wang P.,Beijing Jiaotong University
Zhongguo Tiedao Kexue/China Railway Science | Year: 2015

The tenon-groove joint of the prefabricated structure for open-cut metro station was taken as the research object. The stress evolution law of the joint component, the relationships between the joint deformation and joint opening angle with the loading moment were studied by finite element numerical simulation method. The calculation results were compared with those obtained from the full-scale loading test of joint component. The results of both the numerical simulation and loading tests indicated that, under the most unfavorable working condition of the design axle force of 1 600 kN, the stress of tenon-groove joint parts changed obviously with the increase of loading moment while the stress of tenon end almost remained no change. Accordingly, the tenon-groove for metro station constructed by prefabricated structure could effectively improve the ability of the joint to resist bending moment. The deformation of tenon-groove joint was very small as the loading moment was less than 300 kN·m and the joint deformation changed abruptly as the loading moment was more than 400 kN·m. Therefore, considering the crack resistance requirement of the structure and the mechanical properties of the tenon-groove joint as a whole, the bending moment value for maintaining the tenon-groove joint under normal working state was about 350 kN·m. © 2015, Chinese Academy of Railway Sciences. All right reserved.

Chen B.,Beijing Jiaotong University | Jiang M.,Beijing Jiaotong University | Si B.,Beijing Jiaotong University | Liu J.,Beijing Urban Construction Design & Development Group Co.
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2015

This paper focused on subway network and analysed the different path-choice behaviors among the subway passengers. The generalized travel cost function is formulated based on individual attributes. An individual attributes based logit model is presented for urban subway network flow assignment problem. The corresponding computational method is also proposed. By analysing the SP data for Beijing subway passengers, the major factors that impact the passenger's path choice are found and the differences between different passengers are also obtained. Beijing subway network is used as practical case. The classifications of subway passengers are analysed and the corresponding parameters are estimated. The different assignment methods are used for the same data. The case study has shown that the proposed individual attributes based assignment approach resulted in significantly improved estimation results with less error on the transfer flows than the single class assignment. © 2015, Journal Northern Jiaotong University. All right reserved.

Xu C.,Beijing University of Civil Engineering and Architecture | Qi C.,Beijing University of Civil Engineering and Architecture | Ye F.,Beijing Urban Construction Design & Development Group Co. | Liu X.,Beijing University of Civil Engineering and Architecture | Sun J.,Beijing University of Civil Engineering and Architecture
World Information on Earthquake Engineering | Year: 2015

To study the influence of inertia force on dynamic interaction between underground structure and foun-dation when shear wave propagates along axial direction of long underground structure, static equilibrium equation, free vibration motion equation and forced vibration motion equation were established based on Winkler foundation model and Euler-Bernoulli beam model. By applying mode superposition method we simplified partial differential equation into ordinary differential equation. These equations were solved analytically based on differential operator method. Numerical example was given and the results for static case and forced vibration case were compared. Comparison shows that the influence of inertial force on forced vibration of structure is relatively small in the given case, and is relatively significant when foundation bed coefficient k is small or axial force N is large. ©, 2015, Science and Technology Periodical Press. All right reserved.

Hu S.,Beijing Urban Construction Design & Development Group Co.
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2016

Cavern-pile stations of Beijing 6th line metro were taken as project background in this paper, the ground surface settlement prediction was performed by site measured data of mined metro station in Beijing area. Firstly, the ground surface settlement regularity was analyzed by Cam-clay model. Then, the settlement control of cavern-pile station was performed in every construction sequence based on deformation distribution method. The results show as follows: The stratum loss ratio V1 of cavern-pile station is less than 1%, and the settlement trough width parameter K ranges between 0.65~0.8. The proportion of ground surface settlement is approximately 80% induced by pilot excavation (construction sequence (1)) and arch support in second lining stage(construction sequence (3)), thus construction sequence (1) and (3) are vital to the control of ground surface settlement. The measured value of ground surface settlement basically agrees with the calculated, and the maximum value appears above station center line. © 2016, Editorial Department of Journal of Beijing Jiaotong University. All right reserved.

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