Research On Reconstruction Method Of Vertical Curve For High-speed Dedicated Passenger Railway

High regularity of the railway line is required in high-speed dedicated passenger railway,after many years of the operation of the railway line,due to the wheel-rail force,the regularity of the railway line is difficult to be maintained in the design state,and the change of the spatial position of the railway line causes it to deviate from the design position,and the regularity of the railway line is reduced,which affects the regularity and safety of the operation of high-speed trains and the comfort of passengers.In addition to the reconstruction of the plane curve,the reconstruction of the vertical curve is also required.The longitudinal section of the traditional existing railway is also required to adjust the vertical curve frequently.However,the corresponding adjustment method of the vertical curve is no longer applicable to the high-speed dedicated passenger railway with a large proportion of elevated line.Therefore,It is necessary to conduct research on the reconstruction method of the vertical curve of the high-speed dedicated passenger railway.And the research contents of this paper are as follows:(1)Through analyzing the reconstruction principles,methods and the applicability in the reconstruction of the vertical curve of commonly used methods for the reconstruction of the existing plane curve,such as versine method,deflection angle method and coordinate method,the coordinate method is selected to be the basic principles and method applicable to the reconstruction of the vertical curve for the high-speed dedicated passenger railway.(2)The differences between the reconstruction of the plane curve and vertical curve in high-speed dedicated passenger railway are analyzed from the aspects and ubiety of the alignment,backgrounds and constraints of the reconstruction,data compositions,measurement methods and so on.(3)The precise measurement methods of high-speed dedicated passenger railway are introduced in detail,and the measurement methods and principles of the mileage and elevation data for the reconstruction of the vertical curve are analyzed.It is proved that the precision of the mileage and elevation data measured by the total station with track detection car system based on the track control network can meet the detection requirements of the reconstruction of the vertical curve in high-speed dedicated passenger railway.(4)The study on segmentation methods,fitting methods and optimization methods of the longitudinal section alignment are carried out.In high-speed dedicated passenger railway,the applicability for the the reconstruction of the vertical curve are analyzed through various segmentation and fitting methods commonly used in the reconstruction of the plane curve,and based on slope(grade)method and robust orthogonal least square method,the precise segmentation of the longitudinal section alignment is realized by iterative fitting idea.Based on the the precise segmentation results of the longitudinal section alignment,by creating objective function and setting constraints,the optimal parameters of the straight line and vertical curve that make the objective function reach the minimum are solved.And based on the optimized parameters of the longitudinal section alignment,the elevation adjustments of the rail top surface are calculated.After the fine adjustment of the elevation of the rail top surface,it is necessary to detect the rail corrugation situation and timely perform the operation of rail grinding for the over-limit section.Finally,the reconstruction of the vertical curve in high-speed dedicated passenger railway is realized.