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Chen X.-D.,Beijing Jiaotong University | Chen X.-D.,The Third Railway Survey and Design institute | Li S.-D.,The Third Railway Survey and Design institute | Wang Z.-H.,The Third Railway Survey and Design institute
Tiedao Xuebao/Journal of the China Railway Society | Year: 2011

Due to the developing requirements of building environment-friend type railway, noise barriers have been put into wide application as an effective means of reducting noises. The impulsive pressure is the control factor essential to dynamic design of the noise barrier. The three dimensional model of the high-speed train, noise barrier, and air was built with the ALE method to simulate the whole process of generating train-induced impulse pressures. The distribution and time-histories change characteristics of the impulsive pressures were studied. The law of the train speed, the height of the noise barrier and the distance between the noise barrier and the track center affecting the impulsive pressure were analyzed. The three dimensional model was solved with the parallel computation technique. The influence of the parallee domain decomposition method on the parallel efficiency and speedupratio was studied. The research results provide reference for structure design of noise barriers of high-speed railways. Source


Xudong L.,Wuhan University | Zujie H.,The Third Railway Survey and Design institute
Journal of Computers | Year: 2012

With favorable penetrability to vegetation, LiDAR data is an important data source to generate high precision DEM for reconnaissance and design of railway. To avoid the limitation of the LiDAR data-processing in keeping terrain feature and to satisfy the demand of the reconnaissance and design, this paper presents a high fidelity DEM production method, which successively uses the specialized software and the variety photogrammetry technology. The large scale results of production have proved that the method is feasible and useable. © 2012 ACADEMY PUBLISHER. Source


Wang Y.,Central South University | Liu J.-H.,Changsha University of Science and Technology | Wang X.-H.,Central South University | Cai J.-J.,The Third Railway Survey and Design institute
Yantu Lixue/Rock and Soil Mechanics | Year: 2012

A three dimensional nonlinear finite element model of pile group foundation of a high-speed railway bridge was built. Combined with the corresponding data obtained from field tests, the rules of pile axial force, pile side friction force, soil additional stress, pore water pressure distribution, excess pore water pressure dissipation and settlement of pile group foundation were analyzed. The calculation results show that the axial forces of corner piles are larger than the side piles which are larger than the center piles; and the axial forces of corner piles and side piles reduce greatly along the pile body; and the axial forces of center piles decrease slowly. Moreover, the regular pattern of pile side friction is that the pile side friction measurement of corner piles are larger than the side piles which are larger than the center piles generally; and the amount of relative displacement between pile and soil is bigger on the upper and less on the lower. That is to say, the amount of relative displacement between pile and soil on the upper of pile is larger than on the middle and lower of pile. Furthermore, the soil additional stress and excess pore water pressure generated by external loads mainly concentrate in soil under the pile cap within a certain range; and their attenuation gradients decrease along the depth gradually. With the increasing of the consolidation time, the settlement of pile group foundation arrives to be stabilized. Source


Tong X.-Z.,Central South University | Liu J.-X.,Central South University | Liu Y.,Central South University | Gan J.-X.,Central South University | Zhang L.-W.,The Third Railway Survey and Design institute
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2011

In two-dimensional geo-electric modeling, the tipper response of magnetotelluric (MT) depends on the numerical simulation of traverse electric (TE) mode problem. Firstly, the boundary value problem and variational problem are derived, and finite element method is applied to the modeling. Secondly, the electric field values on each node are obtained by solving the matrix equation of complex coefficients. Lastly, the partial derivatives of the horizontal and vertical electric fields are estimated using differential method; from the derivatives the tipper response of the two-dimensional MT could be calculated. Numerical simulations of two models demonstrate that tipper responses thus obtained include real and imaginary parts or the amplitude, which reflect the horizontal distribution of the abnormal body. Source


Xiao Z.,Tianjin University | Wang Y.-Z.,Tianjin University | Ji C.-N.,Tianjin University | Huang T.-K.,China Communications First Design Institute of Navigation Engineering | Shan X.,The Third Railway Survey and Design institute
Yantu Lixue/Rock and Soil Mechanics | Year: 2010

A quasi static finite element method for stability analysis of the large cylindrical structure considering the cyclic weakening effect of soft foundation under wave load was developed by combining the concept of cyclic shear strength with D-P yield criterion. Then the proposed method was numerically implemented in the framework of the general-purpose FEM software ABAQUS. According to a project, the stability of the large cylindrical structure was analyzed. The results show that the stability safety factor of the large cylindrical structure decreased obviously when strength weakening of soft ground was considered while increased remarkably when the soft clay was reinforced by driving drainage plate. And the stability safety factor of the large cylindrical structure increased obviously with the increment of reinforced depth for the same embedded depth of the large cylinder. Weakening degree of the stability safety factor of the large cylindrical structure is 30% when strength weakening of soft ground is considered; so it is suggested that the strength weakening of soft ground should be considered in practical design. Besides, reinforcement of soft soil by driving drainage plate is an effective way to increase the stability safety factor of the large cylindrical structure when the soft ground can't satisfy the bearing requirement of the structure. Source

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