地铁线路平面圆曲线和缓和曲线限速分析研究

Discussion on Speed Limit of Plane Circular Curve and Transition Curve of Metro Line

地铁线路平面线型分直线与曲线,曲线包含缓和曲线和圆曲线,因此曲线限速可分为缓和曲线限速和圆曲线限速。《地铁设计规范》提出了圆曲线的允许短时超速,但未对缓和曲线允许超速予以说明,由于圆缓曲线限速考虑因素不同,当将圆曲线超速值应用于缓和曲线时,缓和曲线长度往往无法满足相关指标要求。建议将来规范中补充缓和曲线允许的短时超高时变率和动能损失的指标值,提高缓和曲线短时超速,即可与圆曲线短时超速相呼应,更显严谨及便于实际应用。

The plane line type of metro line is divided into straight line and curve,and the curve includes transition curve and circular curve,so the curve speed limit can be divided into transition curve speed limit and circular curve speed limit.The code for design of Metro puts forward the allowable short-time overspeed of circular curve,but it does not explain the allowable overspeed of transition curve.Due to different considerations of circular curve,when the overspeed value of circular curve is applied to transition curve,the length of transition curve is often unable to meet the requirements of relevant indicators.It is suggested that in the future,the index values of allowable short-time super-high time rate and kinetic energy loss of transition curve should be supplemented to improve the short-time over speed of transition curve,which can correspond to the shorttime over speed of circular curve,more rigorous and convenient for practical application.