Study On Dynamic Characteristics And Evaluation Method Of Speed-increasing Turnout In Trunk Railway

Speed-raising turnout plays an important role in trunk railway in China.They are numerous and varied.The structural diseases of speed-raising turnout are mainly concentrated in such aspects as fatigue and nuclear damage of rail,failure and fracture of connecting parts,uneven rigidity of roadbed slab,and water seepage instability of roadbed.The traditional manual static inspection mainly solves the problems such as the over-limit of geometric dimensions,the surface damage of the rail of the switch,and the looseness and failure of connecting parts,etc.,but it is difficult to check and evaluate the working state of the switch under the action of dynamic load.The dynamic characteristics of the turnout can be analyzed by means of the dynamic data obtained from the comprehensive test train or the dynamic test train,and the working state of the switch can be evaluated more objectively.According to the analysis results,a reasonable maintenance scheme of turnout set is developed?Managers have targeted to solve the existing diseases of turnout,reduce the driving safety risk of turnout due to disrepair,and avoid the waste caused by "excessive repair" and secondary diseases of turnout.It is of great engineering significance to master the state of turnout and its disease development trend dynamically and guide the maintenance and repair scientifically.Lateral acceleration of vehicle body is an important factor affecting passengers' riding experience.Spectral analysis of lateral acceleration of vehicle body collected by comprehensive inspection train or dynamic inspection vehicle is conducted by using time-domain,frequency-domain and time-frequency analysis method to explore the correlation between the state of speed-raising turnout and lateral acceleration of vehicle body.The time-frequency distribution of lateral acceleration is obtained by using the short-time Fourier transform to process the non-stationary signal.Through the in-depth analysis of the time-frequency distribution in the turnout area,it is found that the main frequency of the car body's lateral acceleration mainly corresponds to the characteristics of the car body's center rolling pendulum and the car body's horizontal displacement,and the corresponding relationship between the turnout disease and the car body's lateral acceleration.Combined with the actual condition of the turnout,this method is used to optimize the turnout maintenance program.Based on PV and PPV,a weighted comprehensive index(WCI)is proposed to evaluate the turnout state.By using this method,two groups of NO.12 turnouts with different types are compared to verify the practicability of the method.The analysis results of this paper not only have guiding significance and field application value for the speed-raising turnout of the ballast bed section of the existing railway line,but also provide data support for the turnout replacement overhaul,repair and maintenance,and provide reference for the evaluation of the nonballasted-track turnout.