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Li H.-Q.,Inner Mongolia University | Yang W.-L.,China Academy of Transportation Science | Gao X.,ZhongJiaoTongli Construction Co.
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2013

In order to overcome the calculation misconvergence in the analysis of large complicated structure's ultimate bearing capacity with solid element model, the wires and bars in pre-stressed structures were meshed as blocks in the element, and the concrete was simulated with solid degenerated shell element. In the analysis, perfect elasto-plastic model was adopted for reinforced bars and pre-stressed wires, while for concrete, the Ohtani-Chen multiple strengthening model was applied. Meanwhile, the Total Lagrange method was applied to calculate the geometrical nonlinearity effect, and the orthotropic crack model was applied to simulate the concrete cracks. The analysis theory was used to simulate the loading and failure process of a simple hollow board beam, which showed fair accordance with the test results. Then the bearing capacity of a typical 5 span pre-stressed concrete frame bridge with high piers was calculated and analyzed with both the geometrical nonlinearity and material nonlinearity effect considered. The calculation results were compared with that with ABAQUS. The results show that the proposed method can overcome the misconvergence in the calculation induced by the concrete cracks and the real collapse state of the structure can be derived. Source


Li H.-Q.,Inner Mongolia University | Gao X.,ZhongJiaoTongli Construction Co. | Yang J.-G.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Yang J.-G.,China Academy of Transportation Science
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2013

In order to know about permeability of asphalt concrete pavement during early stage and find the recessive disease, permeability test in the laboratory was improved. AC-20 and AM-20 were used to make rut test piece with air voids of 4%, 6%, 8%, 10%, 12% and 14% respectively. Based on permeation and illumination test by using iodine-tungsten lamp, correlation between volume of air voids and permeability, temperature of road surface and permeability were studied. Besides, the correlation was verified by application. The result showed that air voids of asphalt mixture is one of the main factors contributing to road surface temperature in the fine day after rain except solar radiation, aggregate lithological characters, environment and other natural factors. Permeability coefficient shows linear increase with air voids of rut test piece and increases dramatically when air void is larger than 9%; after illumination by iodine-tungsten lamps, difference in temperature of rust test piece increases firstly, then decreases and tends to zero lastly with illumination time. This paper can provide reference for recessive study of asphalt concrete pavement, and basis for time decision-making of preventive maintenance. Source


Feng Z.-X.,Hefei University of Technology | Yuan H.-Z.,Changan University | Liu J.,Anhui University of Architecture | Gao X.,ZhongJiaoTongli Construction Co. | Zhang W.-H.,Hefei University of Technology
Journal of Central South University | Year: 2013

Referring to the 1 248 survey data of rural population in 14 provinces of China, the influencing factors of trip time choice were analyzed. Based on the basic theory of disaggregate model and its modelling method, nine grades were selected as the alternatives of trip time, the variables affecting time choice and the method getting their values were determined, and a multinomial logit (MNL) model was developed. Another 1 200 trip data of rural population were selected to testify the model's validity. The result shows that the maximum absolute error of each period between calculated value and statistic is 3.6%, so MNL model has high calculation accuracy. © 2013 Central South University Press and Springer-Verlag Berlin Heidelberg. Source


Ren W.-F.,Central South University | Ren W.-F.,China Communications Construction Company Ltd. | Gao X.,ZhongJiaoTongli Construction Co. | Wang X.-H.,Central South University | Tu P.,Central South University
Jiaotong Yunshu Gongcheng Xuebao/Journal of Traffic and Transportation Engineering | Year: 2013

Undisturbed soil was drilled for soil test by using geological drilling rig above the tunnel center line. The settlements of tunnel surface and vault were measured by using electronic level. Tunnel horizontal convergence values were measured with JSS30A digital convergence instrument. Pressures among surrounding rock and initial support, initial support and secondary lining were measured with JTM-V2000D vibrating wire pressure gauge. The surrounding rock deformation and pressure of Zhaizigang Tunnel were measured, the surrounding rock deformation rule and mechanical characteristic of tunnel in water-rich full-weathering granite area were got. Analysis result shows that the dividing line of deep and shallow submersion tunnels is 2 times tunnel diameter. Vertical displacement and horizontal displacement appear simultaneously in tunnel entrance. The horizontal convergence stability time of surrounding rock and settlement stability time of vault have little relationship with tunnel depth. The horizontal convergence value and vault settlement increase with the increase of shallow submersion tunnel depth, but they have little relationship with the depth of deep submersion tunnel. Pressures are evenly distributed between surrounding rock and initial support, pressure difference among measurement points of shallow submersion tunnel is little, pressure gradually increases with the increase of tunnel depth. The uneven degree of pressure distribution increases for deep submersion tunnel, pressure value changes very little with the increase of tunnel depth.The pressure between surrounding rock and initial support is greater than that between initial support and secondary lining, the maximum pressure between initial support and secondary lining is not greater than 100 kPa. Source


Feng Z.-J.,Changan University | Wang H.,Shaanxi Expressway Construction Group Company | Wei J.,Changan University | Gao X.,ZhongJiaoTongli Construction Co. | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2015

In order to ascertain the effect of loess gulch on the bearing capacity of bridge pile foundation, for the first time, based on the self-developed platform model test, the model tests can fully reflect the characteristics and work performance of pile foundation in loess gulch area. The change rules of vertical bearing capacity, pile axial force and lateral friction force of the pile foundation with different slopes and pile lengths are analyzed, and some engineering technical advices are given based on test results. The results show that: (1) With the increase of slope, the bearing capacity of piles with the same pile length decreases, the influence degree of bearing capacity increases gradually, and the range varies from 7% to 35%. (2) The pile bearing capacity increases with the increase of pile length to some extent; when the pile length increases to a certain length, the rate of increase becomes slow. (3) The effective pile length with the same buried depth decreases with the increase of slope. (4) The design of bridge pile foundation should fully consider the engineering technology of preventing the soil around piles being eroded in the loess gulch area. © 2015, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved. Source

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