Liu B.,Beijing Jiaotong University |
Wang Z.,China Railway Shanghai Design Institute Group Corporation Ltd |
Xu W.,Tianjin Municipal Engineering Design and Research Institute |
Chen W.,China Communications Construction Company Ltd. |
Wang X.,Beijing Jiaotong University
Open Civil Engineering Journal | Year: 2016
This paper describes comparative experiment on corrugated steel pipe culverts with different stiffness. The two culverts both with 1.2m span and 4m backfill height but with different corrugation pattern and plate thickness were constructed side by side. Displacement, strain and soil pressure at critical points were tested during construction. Two-dimensional (2D) finite element (FE) models were established and the computed values were compared with measured values to verify the effectiveness of FE models and the reasonability of the test. The study shows that the deformation trend is the same but the deformations of the flexible pipe were much larger. Only after the backfill finished and the soil-structure bear the load together the FE simulation could basically reflect the stress state of the structure due to the nonlinearity of soil and the complexity of soil-structure interaction. The larger deformation of the flexible pipe makes the soil-structure interaction obvious, which reduces the pressure of backfill soil on the structure. Therefore realities should be considered when choosing corrugation pattern and thickness of corrugated plates to optimize design and save construction cost. © Liu et al.
Sun K.,Southwest Jiaotong University |
Lu F.,Southwest Jiaotong University |
Qiu W.,Southwest Jiaotong University |
Zhang L.,China Railway Shanghai Design Institute Group Co. |
And 3 more authors.
Modern Tunnelling Technology | Year: 2015
In this paper, a uniform design method is adopted to design a numerical simulation test with 16 levels of 5 factors(surrounding rock density, elasticity modulus, Poisson ratio, cohesive force and internal friction angle) and a 3D calculation is conducted for the construction of a long-span bored metro station by the finite difference method to obtain the values of surface subsidence for different experimental conditions and different procedures. The incremental displacements of 11 observation points induced by the demolition of the temporary support and corresponding rock-soil parameters are used as the input set, and the output set of a BP neural network helps to complete the training and learning. Additionally, the measured displacements induced by the demolition of the temporary support are taken as input parameters and the corresponding rock-soil parameters were inversed. The displacements of the rock-soil mass were obtained by putting all the inversion parameters into FLAC3D for a 3D-simulated calculation, and the rationality of those parameters are verified by measured increments of surface subsidence at 7 measuring points. The results show that the equivalent physical and mechanical parameters of the surrounding rock of a long-span bored metro station can be effectively obtained by a uniform design method and BP neural network in light of the surface subsidence increments induced by the temporary support demolition. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.
Chen L.,Hohai University |
Zhao J.,Guangzhou Metro Group Co. |
Zhang H.,Jiangsu Electrical Power Design Institute |
Lei W.,China Railway Shanghai Design Institute Group Co.
Soil Mechanics and Foundation Engineering | Year: 2015
Although internal erosion causes serious hazards to embankments and dams, studies on the emission of fine soil particles and the development of non-uniform penetration of the soil foundation after suffusion do not go far enough. Given that suffusion development is random and complex, this study employed self-designed equipment to conduct tests under specific conditions. Twelve samples with three different pore size distributions were used to make a comparative analysis on aspects such as piezometric head, flow rate, coefficient of permeability, trend of fine particles, and accumulated sand emissions. Furthermore, the coefficient of permeability, void ratio, movement trend of fine particles in samples, and changes in content of the remaining fine particles were studied. Combined with theoretical calculations, correlations among the movement trend of fine particles in the samples, content of remaining fine particles and uneven changes in the permeability coefficient were shown. Using the relationship between permeability and porosity, we derived a theoretical formula was deduced from the changing amount of accumulated sand emissions over time under fixed upstream total head. © 2015 Springer Science+Business Media New York
Li A.,Jilin Institute of Architecture and Civil Engineering |
Li Y.,China Railway Shanghai Design Institute Group Co. |
Zhao X.,China Railway Shanghai Design Institute Group Co.
Applied Mechanics and Materials | Year: 2013
Semi cover and cut construction have been widely used in solving the traffic problem in narrow area. The main issue of this method is to make sure the safety of temporary road and bridge system. The paper is based on a subway station, it simulates foundation pit with different width-depth ratio through finite element methods and analyzing different pile parameters. The research shows: (1) When use different width-depth ratio the shape of basal heave and the position of maximum value are different. (2) When there is a plastic uplift, the positions of "double-peak" don't change with the width. (3) Increasing the length of pile is better than increasing the diameter of pile to decrease the upheaval of temporary road slab. © (2013) Trans Tech Publications, Switzerland.
Liu S.,East China Jiaotong University |
Wu L.,China Railway Shanghai Design Institute Group Co. |
Zhu X.,East China Jiaotong University
Lecture Notes in Electrical Engineering | Year: 2016
Single catenary system model and three-dimensional mass model of pantograph system were established, and kinetic equation was given in this paper. NARMA-L2 neural network model was introduced and applied to the pantograph– catenary vibration control system, and an active control proposal was designed. Simulation research was done as to the effect of controller for speed of 200 km h−1, 250 km h−1, and 300 km h−1. Also the simulation gets pantograph–catenary contact force and pantograph uplift curve, simulation data were analyzed from four aspects maximum, minimum, average, and standard deviation. Comparative results show that compared with the control without NARMA-L2 model, standard deviation of pantograph–catenary contact force and pantograph uplift is lower much at the set speed. Therefore, pantograph vibration control system based on NARMA-L2 neural network can greatly reduce the vibration amplitude of pantograph–catenary and enhanced pantograph–catenary coupling, thus achieved more stable pantograph– catenary contact and better current collection. © Springer-Verlag Berlin Heidelberg 2016.
Chen M.,Tongji University |
Luo Y.Y.,Tongji University |
Zhang B.,China Railway Shanghai Design Institute Group Co.
Advanced Materials Research | Year: 2014
Finite element model of track in frog zone is built by vehicle-turnout system dynamics. Considering variation of rail section and elastic support, bending deformation of turnout sleeper, spacer block and sharing pad effects, the track integral rigidity distribution in longitudinal direction is calculated in the model. Vehicle-turnout rigid-flexible coupling model is built by finite element method (FEM), multi-body system (MBS) dynamics and Hertz contact theory. With the regularity solution that different stiffness is applied for rubber pad under sharing pad of different turnout sleeper zone, analysis the variation of vertical acceleration of bogie and wheelset, rail vertical displacement and wheel-rail interaction force, this paper proves that setting reasonable rubber pad stiffness is an efficient method to solve rigidity irregularity problem. © (2014) Trans Tech Publications, Switzerland.
Wei H.,Kunming University of Science and Technology |
Yang H.,Kunming University of Science and Technology |
Tian D.-P.,Yunnan Geological Investigation Group CO. |
Wang Q.-H.,China Railway Shanghai Design Institute Group CO.
Advanced Materials Research | Year: 2011
Dam deformation is characterized with periodicity, tendency, randomicity. So dam deformation can be regarded as sum of periodic deformation, tendency deformation, and random deformation, of which periodic and tendency deformation, gained by deterministic method, are researched sufficiently, but study on random deformation is inadequacy. Because dam random deformation at time t is mainly influenced by dam state at time t-1, little influenced at time t-2 or earlier, dam random deformation can be idealized as stochastic process described by Markov chain. In this paper, a new dam safety monitoring model is established using Markov chain, based on statistic model. First, regression analysis was applied to establish dam deformation statistic model, by which dam deterministic deformation can be obtained. Then dam random deformation component can be gained by subtracting deterministic deformation from total dam deformation. Consequently, by analysis of time series of random deformation, transition probability matrix of random deformation can be obtained and used to analyze dam deformation. Case study showed that this new model is superior to traditional statistic model, and can be applied to establish dam safety monitoring model. © (2011) Trans Tech Publications, Switzerland.
Zhu D.,Lanzhou Jiaotong University |
Zhu D.,China Railway Shanghai Design Institute Group Co. |
Zhang Y.,Lanzhou Jiaotong University |
Lin L.,Lanzhou Jiaotong University |
Wang L.,Lanzhou Jiaotong University
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2016
A special-support box girder element was presented to analyze the torsional mechanical behavior of the continuous box girder bridge with special supports. The deformations of axial extension, vertical bending and restraint torsion were considered in the element. The displacements at the beam axis were transformed to the special support point by introducing the element displacement transformation matrix to satisfy the displacement constraint condition at the special support section. The homogeneous solution to the restraint torsion differential equation was adopted as the torsional displacement function of the element and the element stiffness matrix for restraint torsion was derived by applying the initial parameter solution. A three-span continuous box girder model with special supports was analyzed by using the element presented and the calculated results of stresses are in good agreement with the shell element results of ANSYS and the testing results, which verifies the effectiveness of the box girder element. The torsional mechanical behaviors of the continuous box girder with special supports and the corresponding regular box girder under eccentric load were analyzed in detail. The results show that the torque moment, bi-moment, torsion angle and generalized warping displacement of the box girder with special supports are larger than those of the corresponding regular box girder. The distribution of the internal force and displacement of the box girder with special supports is more complicated than that of the regular box girder. © 2016, Central South University of Technology. All right reserved.
He X.,Southwest Jiaotong University |
Guo A.,Southwest Jiaotong University |
Peng X.,Southwest Jiaotong University |
Zhou Y.,China Railway Shanghai Design Institute Group Co. |
And 2 more authors.
Energies | Year: 2015
The advanced traction power supply system (ATPSS) is a new directional development for traction power supply systems, which can totally remove the neutral sections and effectively promote power quality. However, the existing converters suffer from small substation capacity. In this paper, a new configuration based on a three-level neutral point clamped (3L-NPC) three-phase to single-phase cascade converter in a substation is proposed for ATPSS, which can be used to match the capacity of the converter for high voltage and large power applications. The control strategy of the proposed converter is analyzed in depth, and the phase disposition sinusoidal pulse width modulation (PD-SPWM) with phase shift carrier SPWM (PSC-SPWM) is employed in the inverters. Then, the inductance equalizing circuit is applied for the voltage balance on the DC-link. Besides, a LC filter circuit is designed to eliminate the double line-frequency ripple of DC voltage. Afterwards, a simulation model and an experimental prototype are developed, respectively. The simulation results show that the proposed converter in this paper can not only meet the requirements of voltage and capacity for the traction network, but also improve power quality. Finally, the experimental results verify the correctness and feasibility of the proposed control strategy. © 2015 by the authors.
Jin Y.,China Railway Shanghai Design Institute Group Co. |
Wang W.,China Railway Shanghai Design Institute Group Co.
Journal of Geomatics | Year: 2013
This article describes the error influence of using opposite and synchronous observation method with measurement robot, and takes Leiaca TS30 total station as an example for the precision estimation. An example of the Huangpu River crossing levelingis is given to illustrate that this method not only guarantees the precision but also greatly improves the work efficiency at last.