Time filter

Source Type

Liu S.,Shijiazhuang University | Qi Y.,Shijiazhuang University | Feng D.,China Railway 12th Bureau Group Co. | Shi X.,China Railway 12th Bureau Group Co. | Wan T.,Guangxi University
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2012

Based on the complex function, the analytical stress solution of the board containing an elliptical hole, circle hole and line crack defects can be obtained easily. For an elliptical hole with an edge crack, the mathematical conformal mapping function is too complex to get the precise stress function, so there isn't the stress distribution in the existing literature. By the complex function and the finite element method, the plane problem of a plate with a crack emanating from an elliptical hole subjected to uniform tension forces is studied. The stress distributions in the vicinity of the hole and the crack are obtained, and compared with the analytical solutions of the elliptical hole or the line crack only. The stress intensity factors(SIF) are also calculated. It is shown that there are obvious stress concentration effects near the hole and the crack tip. The values of stresses reduce to the subjected loads quickly. Because of the interaction of the hole and the crack, the stress values around the elliptic hole and near the crack increase. Comparisons with available analytic results show good coincidence. The stress distribution of an elliptical hole with an edge crack obtained can provide a theoretical basis for engineering design. © 2012 Journal of Mechanical Engineering.


Xu Z.-L.,The Third Railway Survey and Design Institute Group Corporation | Zhang N.-L.,China Railway 12th Bureau Group Co. | Zhou Z.-C.,Shanghai Kunming Railway Passenger Dedicated Line Hunan Ltd Liability Company | Xu Y.-M.,The Third Railway Survey and Design Institute Group Corporation
Journal of Railway Engineering Society | Year: 2014

Research purposes: Railway tunnel construction process, due to the complex geological conditions, tunnel construction faces more insecurity factors , especially long tunnel. Xuefeng Mountain Tunnel No. 1 of Changsha to Kunming Passenger Dedicated Line faces many high risk factors, such as landslides, sudden inrush of water and mud, large deformation of surrounding rock. According to gradeIrisk management, the specific risk control measures and risk management basic system are proposed for the tunnel surrounding rock deformation, landslides, sudden inrush of water, mud and other risks , in order to achieve quality, investment, construction period and other development goals. Research conclusions: (1) Accurate and complete information is an important basis for the geological survey to identify the risk factors. With the continuous improvement of the tunnel geological survey data, the risk factor identification is gradually deepened, to form a comprehensive, sophisticated risk control measures. (2) Risk assessment of construction drawing stage and construction phase is an important stage of the risk assessment. (3) Risk management of tunnel is a system engineering, organization guarantee is the foundation of risk management success, which depends on the organization and management of design, construction, and construction units. (4) Effective implementation of the risk management system will make sure the tunnel safety, quality, investment, construction period and other ground targets of construction projects met successfully. (5) The research results can provide a good reference for the risk control and management of high speed railway tunnel.


Yang X.,Tongji University | Yao Y.,China Railway 12th Bureau Group Corporation | Zhang Y.,Tongji University | Ye P.,Tongji University
Geotechnical Special Publication | Year: 2010

The Shiziyang tunnel is in passenger dedicated rail line connecting Guangzhou, Shenzhen and Hong Kong. It will be the longest underwater tunnel and have the highest technical level in China. This article describes the tunnel's design and construction schemes, analyzes and summarizes the characteristics of this tunnel, in terms of its geological and hydro geological formations; and defines the strata graphic classification. According to sub-formation and characteristics of the tunnel, this article discusses the problems that may arise in the construction of the tunnel in sub-strata, declares the key points in technology of shield tunneling in three major aspects: soft ground, the upper-soft and lower-hard mixed ground and hard rock (medium hard rock) ground.


Zhang M.-J.,Beijing University of Technology | Zhao M.,Beijing University of Technology | Wang P.-C.,China Railway 12th Bureau Group Co. | Jia D.-P.,China Railway 12th Bureau Group Co. | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

The change rules of the secondary stresses of advanced tunnel segment induced by parallel shield tunnels dirving in close proximity are studied by field tests. The layout of the measured points and the field test methods are introduced, and the change rules of the secondary stresses are analyzed. Furthermore, the relationship between the secondary stresses and the distance of the shield driving face to the measured section are studied. Statistical analyses of the maximum and the stabilized magnitudes of the secondary stresses are carried out. The results of the field tests show that there will be sharp change of the secondary stresses when the hind shield is driven to the measured section, the circumferential secondary stresses in the intersection of horizontal diameter with circumference of the tunnel will be laid, and the magnitudes of the circumferential secondary stresses will be greater than those of the longitudinal secondary stresses. The results may be applied to the quantitative assessment of the construction interaction of shield tunnels in close proximity and is regarded as references to the design and construction of this kind of shield tunnels.


Zhang A.,Beijing Jiaotong University | Zhang A.,China Railway 12th Bureau Group Ltd Company | Bai M.,Beijing Jiaotong University | Xu Z.,Beijing Jiaotong University | And 2 more authors.
Advanced Materials Research | Year: 2011

Aiming at the safety management of the Beijing subway line 10 in the construction, the technical system research of safety management in the underground railway engineering construction were discussed including the objective management of safe production, field safety standards, the founding method for safety management system. The contents of responsibility system for safe production and the contents of safe-education and safe-inspection for workers were also studied. Safety precautions and Safe checkage standards were established during the railway's tunnel construction. © (2011) Trans Tech Publications.


Zhang A.,Beijing Jiaotong University | Zhang A.,China railway 12th Bureau Group Co. | Bai M.,Beijing Jiaotong University | Xu Z.,Beijing Jiaotong University
Advanced Materials Research | Year: 2011

With Beijing subway Suzhou street station project, the composition of safety system for construction phase was studied. The safety responsibility of administrative department, technical branch, and operational department and construction personnel was clarified. The division and cooperative relationship were also analyzed. Meanwhile the construction techniques for shallow burial and dim excavation to improve safety performance for the whole project as well as surrounding environment under complicated city environment were discussed. © (2011) Trans Tech Publications.


Zhang M.-J.,Beijing University of Technology | Zhao M.,Beijing University of Technology | Jia D.-P.,China Railway 12th Bureau Group Co. | Wang P.-C.,China Railway 12th Bureau Group Co.
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2013

During construction of small interval shield tunnel, the magnitude of the advanced tunnel stresses changed. The magnitude and changing regularity of the advanced tunnel segment secondary stresses were studied by field test on a practical project. By means of steel sting surface strain gages and frequency instrument readings, in-situ monitoring on the circumferential secondary stresses and the longitudinal secondary stresses were carried out in a small interval shield tunnel of Beijing subway. Lasted curves of the circumferential secondary stresses and the longitudinal secondary stresses were given by analysis of the measured data, and a comparative analysis on maximum secondary stresses and stabilized secondary stresses in different monitoring point was made. The analysis results of the measured data show that the circumferential secondary stresses is pressure, their magnitude is greater than those of the longitudinal secondary stresses, and the maximum magnitude takes place in the intersection of horizontal diameter with circumference of the tunnel. The maximum magnitude of all measured circumferential secondary stresses is 12.77 MPa in this project case. The results may be applied to quantificational assessment to the interaction of small interval shield tunnel during construction and conducted as reference material to design, construction and field test of shield tunnel.


Huang Z.,China Railway 12th Bureau Group CO. | Zeng X.,State Key Laboratory of Silicate Material for Architecture | Gao Z.,China Railway 12th Bureau Group CO. | Wang X.,China Railway 12th Bureau Group CO. | Wang F.,State Key Laboratory of Silicate Material for Architecture
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2013

The effects of material adding order, the ratio of asphalt to cement(ma/mc) and the ratio of sand to cement(ms/mc) on the compressive strength of high elastic modulus cement and asphalt mortar (CAM) are studied. Results show that higher compressive strength and more convenience for construction are acquired using the adding order in sequence of water, dry-mixed mortar, emulsified asphalt. The dry mixed mortar is composed of cement, expansive agent, sand and admixture. The compressive strength decreases with the increase of ma/mc, and the dropping tendency is more obvious when ma/mc is from 0.35 to 0.40. And the optimum ms/mc is obtained. By optimizing mix design, 1 d, 7 d, 28 d compressive strength of CAM reach 3.06 MPa, 11.55 MPa, 17.0 MPa respectively with ma/mc of 0.35, ms/mc of 1.1, W/B of 0.58.


Wang X.-F.,China Railway 12th Bureau Group Co.
Journal of Railway Engineering Society | Year: 2013

Research purposes: Combined with construction of the Tiantaisi Tunnel of the Dazhou-Chengdu Railway, the experimental study was done on the air tightness of the concrete used for the high gas tunnel to find the influence factors and influence law on the concrete gas tightness for providing the technical parameters for making up the gas-tightness concrete and its appliable control in high gas tunnel construction. Research conclusions: (1)The water-binder ratio of the air-tightness concrete should be less than 0.4, no bigger than 0.45. (2)The silt content of the fine aggregate should be not more than 2.5%. The silt content of the coarse aggregate should not be more than 40 mm, with maximum grain size of no more than 40 mm. (3)The elongated flaky particle content of the coarse aggregate should be strictly controlled, and the ratio of the sand and the aggregate should be more than 36%, and the ratio of the sand and the aggregate should be big as much as possible if allowable. (4)The binder content of the air-tightness concrete should be more than 380 kg for 1 m3 concrete. (5)The silica fume and fly ash are good for improving the air tightness of the concrete. (6)The water reducer and compacting agent are able to improve the air tightness of concrete. When many additives have to be used, their adaptabilities should be tested to make them adaptable each other for obtaining the best air tightness. (7)The C-S-H alkalinity of the cement hydration product can be decreased and compactness can be increased by using silica fume and fly ash. In this way, the directional arrangement of Ca(OH)2 at the aggregate interface can be improved, the production of ettringite can be reduced and the air tightness of concrete can be enhanced. (8)The research results can be used in preparation and construction of air tightness of concrete for the gas tunnel.


Zhao N.-Q.,China Railway 12th Bureau Group Co Ltd
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2010

Based on the engineering background of Jing-Hu high speed railway and the actual situation of natural sand shortage, artificial sand high performance concrete was prepared. The effects of mud content, water consumption and sand ratio on the properties of concrete were investigated. The mix proportion of C30 and C35 artificial sand high performance concrete were obtained, which provide a reference for the application of artificial sand in railway project concrete.

Loading China Railway 12th Bureau Group CO. collaborators
Loading China Railway 12th Bureau Group CO. collaborators