Experiment And Numerical Simulation Of The Dynamic Response Of The Wuhan-guangzhou Passenger Line Roadbed

With its comprehensive advantages such as the high speed, economical, high safety and comfortable performance, the high-speed railway has been developed rapidly all around the world. China has greatly improved the train speed by studying and improving the high-speed railway,such as building new fast passenger traffic special line and raising the speed of existing railway. Meanwhile, the high-speed intensifies the dynamic interaction of wheel/rail system. The paper is based on the ground of the typical section of Wu-Guang passenger railline and the scientific and technological project of the ministry of Railways, to adopt theoretical analysis,integrating field investigation and numerical simulation, studying on the characteristic of dynamical response of surbgrade structure of the ballastless track under trainload,the main research work and conclusion as follows:(1) It has been gained on parameter obtainment field investigation of the topical section with cross holemethod and down-hole method, the dynamics parameters (dynamic elastic modulus,the dynamic shear modulus,the dynamic bulk modulus) of the grading macadam, A,B fillers, subgrade body and foundation soil had beem gained.(2) Combined with the subgrade design of the engineering field and foundation treatment situation, chose the topical section of road embankment and road cutting, determined field test project,chose monitoring equipment and testing element,made feasible project of the subgrade dynamic response test.(3) Combined with the'Linked regulating and testing'of Wu-Guang passenger railline, the dynamic responses (containing dynamic stress, dynamic displacement, vibration acceleration and vibration velocity) of subgrade were tested with the CRH2 train-set running at the speed between 180～350 km/h. Through data acquisition and analysis, the dynamic response time-history curve, the change law of dynamic response to depth and to running speed were obtained. (4) Based on the code, the attenuation of the dynamic stress with depth and the amplitude of dynamic displacement of subgrade top were analyzed. Then comparative analysis with the measured results were carried out. These can provide theory basis for subgrade structure design. Besides, relationships of elastic modulus and deformations on surface layer of subgrade bedding facing and roadbedof were discussed.(5) Using the commercial software FLAC3D, subgrade dynamic models of the test sections were established by the finite difference method. Then numerical simulation analysis about the dynamical response of subgrade structure when high-speed trains are working was carried out. Finally, through comparing the calculation results with measured results, the analytical models and calculation parameters are proved to be reasonable.