高速公路改扩建项目超高设置探讨

Discussion on Superelevation Setting of Expressway Reconstruction and Expansion Project

针对高速公路改扩建项目,回旋曲线不够设置增长了的超高渐变段的问题。将超高过渡段分为两部分,克服路拱坡超高过渡段由完成外车道横坡从路拱坡到零坡的改变所需要道路长度构成,正超高过渡段由完成外车道横坡从零坡到全超高的改变所需要道路长度构成。分析汽车在回旋曲线行驶的受力变化,提出解决办法一:将克服路拱坡超高过渡段设置在直线段里,将正超高过渡段设置在回旋曲线里。再通过分析回旋曲线长度控制因素、美国和中国公路设计规范关于超高渐变率的相同点和不同点,提出解决办法二:多车道路面超高时引入车道调整系数,来适当提高超高渐变率,从而达到减小超高渐变段长度的目的。通过其中一种方法或者两者结合,来解决回旋曲线不够长的问题。

For expressway reconstruction and expansion projects,the spiral curve is not enough to set the growing superelevation transition section.The superelevation transition section is divided into two parts.The superelevation transition section to overcome the crown slope is composed of the required road length to complete the change of the cross slope of the outer lane from the crown slope to the zero slope,and the positive superelevation transition section is composed of the required road length to complete the change of the cross slope of the outer lane from the zero slope to the full superelevation.This paper analyzes the force change of the vehicle when driving on the Spiral curve,and puts forward the solution 1:set the superelevation transition section to overcome the crown slope in the straight line segment,and set the positive superelevation transition section in the spiral curve.Then,by analyzing the control factors of the length of the spiral curve and the similarities and differences between the American and Chinese highway design specifications on the superelevation transition rate,the solution 2 is proposed:when the multilane pavement is superelevated,the lane adjustment coefficient is introduced to appropriately improve the superelevation gradient rate,so as to reduce the length of the superelevation transition section.The problem that the spiral curve is not long enough can be solved by one or both of these methods.