喇叭形互通立交设计要点分析

Analysis on Design Points for Trumpet-shaped Interchanges

针对喇叭形互通立交设计中存在的出口匝道减速车道分流鼻处平面指标如何选用、跨线主匝道大纵坡起坡位置距离收费站的长度取值、如何合理压缩被交路侧喇叭头工程规模,提出根据历史事故率及运行速度模型,确定出口匝道减速车道分流鼻附近控制曲线半径及缓和曲线参数取值;根据停车视距,确定跨线主匝道大纵坡起坡位置距离收费站的长度;通过压缩被交路侧半直连匝道指标及喇叭头曲线半径来减小工程规模的设计方法,为设计人员在设计类似互通立交时提供参考。

Aiming at the selection of plane indicators at the diversion spot of the deceleration lane on the exit ramp in the design of trumpet-shaped interchanges,the length value of the distance from the starting point of the large longitudinal slope of the cross line main ramp to the toll station,and how to reasonably compress the scale of the trumpet head project on the side of the intersection,the control curve radius and transition curve parameter values near the diversion spot of the deceleration lane on the exit ramp are determined by putting forward the model based on historical accident rate and operating speed;based on the stopping sight distance,the length of the starting position of the large longitudinal slope of the cross line main ramp from the toll station is determined;the design method of reducing the engineering scale by compressing the indicators of the semi-direct ramp on the side of the intersection and the radius of the trumpet head curve can provide reference for designers when designing similar interchanges.