| The precondition of the development of high-speed railway is safety, reliability and ride comfort that are decided by the high quality and high reliability of all aspect of the railway system. The transition section is one of the must key technologies. The thesis which is combined with the state natural science fund item has studied the dynamic response characteristics of the different conditions' culvert-culvert transition sections under the train load influence. It has adopted the combination of numerical modeling and field test, on the ground of the Wu-Guang passenger railline and on the basis of lots of relevant research at home and abroad. It has gained a number of the test datas and research findings which is valuable for the actual construction. The main research work of this dissertation gained can be summarized as below.(1) Research precept about the dynamic response of culvert-culvert transition section on the WuGuang passenger line DK1252+679～+731 has been instituted: precept design,on-site implementation,data processing and analysis of parameter obtainment test; the finite element simulation model's built by ANSYS,research and analysis of the dynamic response characteristics of transition section on the model; field dynamic test,comparative analysis between simulation and field test.(2) It has been gained on parameter obtainment tests that the average E_d of grading macadam, A,B fillers, clay layers were 1716MPa,793MPa,596MPa and the average G_d of grading macadam, A,B fillers, clay layers were 659MPa,295MPa,219MPa.(3) Built the finite element simulation model of culvert-culvert transition sections by ANSYS and simulation analyse the dynamic response characteristics of transition sections on the model. The main results of simulation analysis include:①Under the 350km/h speed of train, the dynamic response characteristics of culvert-culvert transition sections can be described as follows. Dynamic displacement distributes into "M"-shaped in the longitudinal direction. Each dynamic response decreases with increaseing depth, among which dynamic displacement decreases slowly and the others three decrease as hyperbolic or exponential curve.②The impact of the train speed can be described as follows. When train speed increases from 150 km/h to 350 km/h, the dynamic responses of transition sections imcrease slowly. When train speed increases from 350 km/h to 400 km/h, dynamic displacement,acceleration and vibration velocity increase quickly on the ordinary subgrade of A,B fillers. Thus only if the structure of the ordinary subgrade or the engineering performance of A,B fillers is improved, the train speed could increase.③Increase of subgrade surface layer's thickness can improve dynamic responses of ordinary subgrade, especially under the rail. When train speed increases, the improvement becomes more.④The distance between two culverts' centers has a great influence on dynamic displacement but little on the other three. When the distance is 43.2m, dynamic displacement is maximum and 12% more than the other distances.(4) It indicates that test data almost accord with gaussian distribution to analyse field dynamic test data. With comparative analysis between simulation and field test, the difference is a little and main transformation is similar as follow. Train speed increases and dynamic responses increase. Under subgrade surface layer, acceleration decreases as hyperbolic or exponential curve. In the longitudinal direction , dynamic stress is large on the culverts and small in the middle. Dynamic displacement on the subgrade surface distributes into "M"-shaped in the longitudinal direction.(5) It is indicated the value and distribution of dynamic displacement,dynamic stress,acceleration and vibration velocity with a variety of conditions by dynamic test and simulation analysis, which would provide an important reference for the design and construction of adjacent transition sections. |
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