Spatial Detailed Design Theory And Experimental Research On Ballastless Turnout System On Bridge In High-speed Railway

With the construction and development of high-speed railway, a considerable number of welded turnouts will be set on huge bridge, super large bridge or elevated structure due to high running comfort and stability requirements, environmental and geological conditions limit. The ballastless turnout on bridge in high-speed railway not only combines technical characteristics of continuous welded rail on bridge, welded turnout, ballastless track and long-span bridge, but also derives a series of new technical difficulties, which has become a major technical problem in high-speed railway track engineering research field.Based on investigation and analysis on literature at home and abroad, a spatial detailed coupled model of ballastless turnout on bridge in high-speed railway is developed using large system and co-simulation theory. The parameter affection laws and typical design difficulties are researched systematically with static and dynamic analysis method, and comprehensive field tests are designed and carried out. The systematic check calculations and assessments are performed in typical station, which has guided the design of ballastless turnout on bridge in Zhengzhou-Xian high-speed railway successfully. The main research works are as follows:(1) Spatial detailed coupled model of ballastless turnout on bridge in high-speed railway is established.Based on interaction mechanism of high speed vehicle-welded turnout-ballastless track-bridge-pier, static and dynamic spatial detailed coupled model of ballastless turnout on bridge in high-speed railway are firstly established. The model is compromised of vehicle, turnout, track, bridges, piers and interaction modules, which not only simulates actual dimensions of ballastless track and bridge, but also takes into consideration of detailed factors and nonlinear characteristics of different parts.(2) Using laboratory and field tests, the reasonable values of key design parameters of ballastless turnout on bridge in high-speed railway are researched.The existing majority parameters are suitable for common and speed-raising turnouts, which can’t meet the requirements for design of ballastless turnout on high-speed bridge. Focusing on the shortcomings of existing research, the laboratory tests on fastener and spacer block resistance are carried out, combining analysis of existing researches and field trials about mortar layer resistance, braking force coefficient ect. The reasonable values of key parameter are proposed, and the design parameter system of ballastless turnout on high-speed bridge is established.(3) Mechanical properties and parameter influence laws of ballastless turnout on bridge in high-speed railway are researched systematically.With the spatial detailed coupled model, the interaction mechanism of high-speed turnout-ballastless track-bridge-pier system is revealed. The mechanical properties of ballastless turnout on high-speed bridge under different loads are analyzed, and the influence law of main parameters are studied systematically, including heel structure type, fastener resistance ect. The reasonable design suggestions are put forward.(4) With combination of static and dynamic analysis method, the key technical difficulties of ballastless turnout on high-speed bridge are solved.Focusing on the shortcomings of existing research method, the method of combining static and dynamic analysis is proposed for the first time. The influences of temperature-vehicle coupled load field, relative location of turnout and bridge, and reasonable simply supported beam set mode between turnout beams are analyzed deeply, which provides a new research approach of ballastless turnout on bridge.(5) Field tests about ballastless turnout on high-speed bridge are designed and carried out, and the spatial detailed coupled model is verified.The field tests of ballastless turnout on high-speed bridge are carried out in Zhengzhou-Xi’an railway Weinanbei station and Beijing-shanghai railway Xuzhoudong station. The actual force and deformation law are acquired, and spatial detailed coupled model is verified. Some design parameters are grasped, include wheels rolling influence value, ballastless track temperature distribution ect.(6) The check calculation and assessment index and method for ballastless turnout on bridge in high-speed railway are established.The check calculation index and assessment method of ballastless turnout on bridge in high-speed railway is established systematically from static and dynamic combination view. With theoretical analyses and field tests, the check calculations and assessments of ballastless turnout on high-speed bridge in Zhengzhou-Xi’an railway Weinanbei station and Beijing-shanghai railway Xuzhoudong station are performed comprehensively.