Design method for railway curves based on "six-degree two-stage transitional curves"

Abstract

The present invention discloses a railway curve line designing method based on "sextic two-segment transition curve". The method is characterized in that a rail line of a railway is designed as the following equations: plane curve equation: y1 = 2L<2> / 15R [3(x / L)<5> - 2(x / L)<6>] [0, L / 2]; y2 = L<2> / 120R [32(x / L)<6> - 144(x / L)<5> + 240(x / L)<4> - 160(x / L)<3> + 60(x / L)<2> - 12(x / L) + 1] [L / 2, L] (1); facade ultra-high equation: h1 = 8H [(x / L)<3> - (x / L)<4>] [0, L / 2]; h2 = H [8(x / L)<4> - 24(x / L)<3> + 24(x / L)<2> - 8(x / L) + 1] [L / 2, L] (2); wherein a ZH point (a straight-spiral point) is used as the original point, the extension direction of a straight rail is used as the positive direction of the x axis, and one side of the curve is used as the positive direction of the y axis; L is the length of a transition curve; R is the radius of curvature of a circular curve; and H is the elevation of an outer rail of the circular curve in the design. Compared with existing traditional transition curves in our country, the present invention provides a curve with a higher curve continuous order, greatly improves the smoothness of the curve segment of the railway, and eliminates serious vibration source caused by unsmooth geometry of the curve segment of railway, and avoids impact between the rail of the transition curve segment and trains.

Description

technical field [0001] The invention relates to traffic and transportation road engineering, which can be used for line selection and line design of railway lines and high-grade highways. In particular, it relates to a design method for railway curves based on a "six-degree two-stage transition curve". Background technique [0002] Orientation changes of railway lines (including high-grade highways, the same below) are usually realized through arc-shaped curves. However, if the straight line is directly connected to the arc-shaped curve, there will be a sudden lateral acceleration when the vehicle enters the curve, that is, centripetal acceleration. When the vehicle is used as the frame of reference, the vehicle itself and its passengers or goods will suddenly experience an inertial centrifugal force pointing to the outside of the curve. The greater the speed of the vehicle and the greater the curvature of the curve, the greater the inertial centrifugal force. This will h...

AI Technical Summary

Problems solved by technology

However, doing so brings a new problem: the coordination relationship between track level and facade dynamics is destroyed, making the vehicle in the so-called "abnormal running" state, which will also adversely affect the stability and safety of the vehicle's operation.

However, the façade of the third-degree parabolic transitional curve is a straight slope, and a knuckle is formed at the ZH point and the HY point, that is, the tangent (G 1 ) is discontinuous, when the vehicle passes, it is bound to produce wheel-rail impact force

In addition, ballastless rails are commonly used in my country's high-speed railways today, and the random smoothness of the tracks has been greatly improved. The geometric smoothness of transitional curves and vertical curves has become the main contradiction affecting the stability and safety of vehicles.

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