【作者】 李玉娟；

【导师】 李杰；

【作者基本信息】 武汉工程大学 ， 防灾减灾工程及防护工程， 2011， 硕士

【摘要】 随着改革开放的进一步深化及国民经济的迅速发展,我国的城市化进程步伐加快。从“十二五”开始,中国将用20年的时间解决“半城市化”问题,使中国的城市化率在2030年达到65%。伴随着城市化进程的加速,城乡结合部道路交通安全问题也日益突出。城乡结合部道路是连接城市与乡村的纽带,极大地带动着周边经济的发展。而城市化进程过快与城乡结合部道路建设及交通管理相对滞后之间的矛盾致使城乡结合部道路交通安全问题尤为突出。据有关资料显示,大约50%的城市道路交通事故发生在城乡结合部,且事故后果严重。深入研究城乡结合部过渡段交通安全问题,从道路线形设计方面探索其改善途径,预防和控制事故的发生,是摆在我们面前亟待解决的问题。文章首先讨论了一般道路线形与交通安全的关系。主要分析了一般道路的平面线形诸要素,如直线长度、圆曲线半径、平曲线长度、转角、曲率变化率、视距、缓和曲线长度等对交通安全的影响;讨论了一般道路的横断面布置中,路基宽度与路面宽度对交通安全的影响。二者与亿车公里事故率的关系均为随着宽度的增加,交通事故率首先降低,而当路面宽度增加到一定值时,事故率又开始上升;通过以上的分析与讨论,作者认为在进行城乡结合部过渡段设计时,在考虑交通安全的前提下,必须认真分析研究过渡段平面线形各要素及横断面布置形式,以减少交通事故的发生。其次,在对城乡结合部定性、定量描述的基础上,界定了城乡结合部的范围,城乡结合部是城市化发展到一定阶段产生的一种兼具城市和农村双重特征的特殊经济地理单元。讨论了城乡结合部的交通系统组成,包括交通参与人、道路、车辆及交通环境,并对各自的特征做出分析;界定了事故多发地段,即城乡结合部过渡段的范围,认为城乡结合部过渡段的长度约为3-10公里。过渡段的平面线形由曲线和直线组成,文中选取一种典型线形即两圆曲线夹一直线展开研究。在进行过渡段平面线形优化时,圆曲线半径和直线段长度是两个最关键的控制指标。本文在理论研究时对可能行车速度按照等差为5km/h取值,分别针对六种类型的速度过渡进行计算。其中,直线处行车速度为初始驶入行车速度与过渡段可能行车速度的平均值,并假定为匀速;近城端圆曲线处取驶入行车速度与直线段处行车速度的均值,而远城端圆曲线处行车速度取直线段处行车速度与远城端公路可能行车速度的均值。通过对比分析认为,远城端的一般最小半径比近城端大。同时,计算所得的一般最小半径均是极限最小半径的1.2~1.5倍。推荐的一般最小半径与各对应过渡区间的最大极限最小半径比较相当。在实际工程中,为了满足行车安全性要求,设计采用的圆曲线半径的极限最小半径和一般最小半径以及直线段最小长度均不应低于推荐值。再次,文章分析了城乡结合部过渡段横断面规划及设计中存在的问题,指出眼界道路性质、道路等级、设计速度、地下管线的布置等因素对横断面布置的影响。通过分析城市道路与城郊公路的典型横断面布置形式,采用三级平顺渐变设计理念对不同速度过渡段城市道路与公路典型横断面衔接做出尝试性优化设计,主要包括城市三幅路与公路单幅路、双幅路及城市四幅路与公路单幅路、双幅路。最后,运用基于层次分析法的多级模糊评价方法对城乡结合部过渡段线形进行了评价。指标体系共包括线形指标、速度指标、视距指标和环境指标四个方面共17个指标,在确定时对线形几何要素进行了次级详细划分。评价过程分为评价因素集的建立、评语集的确定、建立隶属函数判断矩阵几部分构成,并针对某过渡段进行了算例检验,得出了正确结论。研究结论对过渡段道路线形设计有一定的工程指导作用。更多还原

【Abstract】 With the further deepening of the reform and opening and the rapid development of national economy, the pace of urbanization of our country are accelerating. Starting From "The Twelfth Five-Year Plan", China will spend 20 years to resolve "peri-urbanization" problem, so that China’s urbanization rate will reach 65% in 2030. With the acceleration of urbanization, road traffic safety issues of urban-rural fringe are becoming increasingly prominent. The roads of urban-rural fringe are the cohesive tie to connect the cities and villages, promoting the economic development of the surrounding greatly. However, the contradiction between the rapid process of urbanization and the relatively lagged road construction and traffic management of urban-rural fringe causes road traffic safety issues of urban-rural fringe particularly outstanding. Relevant data shows that about 50% of the urban road traffic accidents took place in the urban-rural fringe, and the consequences were serious. Further study of traffic safety of urban-rural fringe transition section and exploring improved approaches from the road alignment design to prevent and control accidents, are urgently need to be solved in front of us.The article firstly discussed the relationship between the general road alignment and traffic safety, including the general road horizontal alignment elements, such as length of straight line, circular curve radius, flat curve length, corner, curvature rate, stadia and gentle curve length. Moreover, this paper discussed the influence of the subgrade width and pavement width to traffic safety in the general cross-sectional arrangement, the relationship with accident rate per million vehicle kilometer are that the traffic accidents firstly reduces as the increase of width, when the width increases to a certain value, the accident rate begins to rise. Through the analysis and discussion, the author believed the urban-rural fringe transition section design, considering the premise of traffic safety, must carefully study the elements of horizontal alignment of transition section and the forms of cross-sectional decoration in order to reduce traffic accidents.Secondly, the scope of the urban-rural fringe has been defined based on the qualitative and quantitative description. Urban-rural fringe is a special economic geography unit with double feature of urban and rural as the urbanization developed to a certain stage. Then the traffic system composition and their features of urban-rural fringe were discussed, which included traffic participants, road condition, vehicles and the traffic environment. The paper defined the scope of the accident black spot, namely urban-rural fringe transition section, believed that the length of which was about 3-10 kilometers. The horizontal alignment of transition section was composed by curve and linear. This paper selected a kind of typical linear to research namely two circular curves connecting a straight line.During the optimization of horizontal alignment transition section, the circular curve radius and length of straight line were thought to be the most critical control targets. In this paper, theoretical studies on the possible speed in accordance with the arithmetic for the 5km/h values, respectively calculated six types of transition speed. Among them, the straight-line speed at the initial segment into the driving speed and the transition may be the average speed and was assumed to be uniform; the speed of circular curve near the city were the average value of straight line speed and the initial speed, and the speed of circular curve far from the city were the average value of straight line speed and leaving speed. By comparing the results, it was believed the general minimum radius of the rural-side was larger than urban-side. Meanwhile, the calculated general minimum radius was generally 1.2 to 1.5 times of the optimum minimum radius. The general minimum radius recommended nearly equaled to the maximum value of optimum minimum radius. In practical engineering, the design value should not be less than the recommended value.Moreover, this paper analyzed the problems existing in the design of cross-section of urban-rural fringe transition section, and pointed out the effects which produced by the nature of road, grade, design speed, layout of underground pipelines and other factors. By the analysis of the typical cross-section layout of urban roads and suburban highway, optimization design was made by using the three different graded smooth speed transition design concept, mainly including urban three width road and highway single road, double width road, urban four width road and highway single road, double width road.Finally, based on the analytic hierarchy process (AHP) multi-grade fuzzy evaluation method, alignment of transition section at urban and rural fringe was evaluated. Index system included four aspects 17 indexes in total, which were the linear index, speed index, stadia index and environmental index. The evaluation process was divided into the set of evaluation factors, the establishment of comments, the establishment of subordinate function judgment matrix, and the example was text and it showed correct conclusions, which would play a guide role on the road alignment design of transition section at urban and rural fringe.更多还原