山地城市左入式立交匝道关键设计指标技术研究

发布时间：2018-12-30 18:04

【摘要】：相较于平原城市,山地城立体交叉在规划、设计上具有特殊性,受到诸多因素的制约。以大型山地城市重庆主城区为例,城市土地高强度开发,城市交通建设用地受到严重制约,城市道路供给增长速度远低于机动车保有量增长速度。重庆市主城区机动车保有量自2007年以来以年均15%的速度增长,截止2014年底机动车保有量达到115.1万辆。在城市道路发展方面,主城区道路长度在经历了2007年至2010年的快速增长后,自2010年后总体处于缓慢增长,年平均增长率不足4%。截止2014年底,重庆市主城区道路总长度为3730千米。由此可见山地城市由于受用地所限,城市道路的发展在量上受到严格的制约,其道路建设用地受到山区地貌及城市发展所限。为解决城市道路拥堵问题,需要在已建道路质量上下功夫,提高通行能力,改善通行质量。城市道路原状交叉口改建立交就是对已建道路质量进行提升,但由于山地城市平交口周围用地大部分已开发,拆迁费用高昂,且十分不经济,因此改建立交匝道布线受制约,难以迂回布线,且受左转交通需求、相交道路等级等制约,立交等级普遍较高。为满足用地限制、左转交通量需求及立交等级三个条件,重庆市古木峰平交口改建立交时采取了“左出左进”的定向左转匝道即“左入式匝道”。由于我国车辆靠右行驶,车辆驾驶室位于车辆左前方,因此驾驶员左右视野不同,右侧视野较左侧差,左入式立交匝道要求匝道车辆像右侧变道进入主线。因此存在较大安全隐患。本文首先对左入式立交匝道进行定义,然后根据左入式立交匝道特点,基于城市立交建设用地制约、相交道路性质、左转交通量需求,探讨了其在城市立交规划建设中的适用性。对重庆市古木峰立交左入式立交匝道交通特性实地观测,发现匝道入口连接部是主要的交通流冲突区,存在大量交通冲突。对车辆盲区进行研究,探讨由于车辆本身的物理性遮挡盲区、驾驶室位置导致的盲区、车辆左右侧后视镜盲区差异,并探讨了这种差异所导致的安全隐患。在安全隐患的基础上对左入式立交匝道的安全设计进行探讨:车辆左右盲区经过研究发现确实存在差异,但我国的规范并未体现出这一点差异。匝道入口连接部存在交通流集中冲突。在此基础上,针对入口连接部各相关指标提出安全设计的建议。并以古木峰立交左入式匝道为例进行优化设计,根据规范共设计出三种不同形式的入口匝道连接部。以古木峰立交实际交通流量及交通特性为数据基础,采用VISSIM仿真软件对三种形式的入口连接部进行仿真分析。以不同交通流量下三种形式的排队长度、延误时间等数据作为评价其拥堵程度的指标,进而判断其交通冲突程度。
[Abstract]:Compared with plain cities, mountainous cities have particularity in planning and design, which are restricted by many factors. Taking Chongqing's main urban area as an example, urban land development is high intensity, urban traffic construction land is severely restricted, and the growth rate of urban road supply is far lower than that of motor vehicle ownership. The number of motor vehicles in Chongqing's main urban area has increased by an average of 15 percent since 2007. By the end of 2014, the number of motor vehicles has reached 1.151 million. In the aspect of urban road development, after experiencing the rapid growth from 2007 to 2010, the road length of the main urban area has been growing slowly since 2010, and the annual average growth rate is less than 4%. By the end of 2014, the total length of roads in Chongqing's main urban area was 3730 km. It can be seen that the development of urban roads is strictly restricted in quantity due to the limitation of land use in mountainous cities, and the land for road construction is limited by mountain landforms and urban development. In order to solve the problem of urban road congestion, it is necessary to work hard on the quality of built roads, improve the capacity and improve the quality of traffic. The reconstruction of the urban road intersection is to improve the quality of the constructed road. However, because most of the land around the horizontal intersection in the mountainous city has been developed, the cost of demolition is high and the relocation is very uneconomical, so the reconstruction of the ramp layout of the interchange is restricted. It is difficult to circuitous routing, and by the left turn traffic demand, intersecting road grade and other constraints, the grade of interchange is generally high. In order to meet the limitation of land use, the three conditions of left turn traffic demand and grade of interchange, the directional left turn ramp of "left out left turn in" is adopted when rebuilding the interchange at Pingjiaokou of Gumu Feng in Chongqing. Because the vehicle runs on the right in our country, the vehicle cab is located in the left front of the vehicle, so the driver's right visual field is different, and the right side view is worse than the left. The ramp of the left entry interchange requires the ramp vehicle to change the ramp as the right side to enter the main line. Therefore, there are large security risks. In this paper, we first define the left-in interchange ramp, then according to the characteristics of the left-in interchange ramp, based on the urban interchange construction land constraints, intersecting road nature, left-turn traffic demand, This paper discusses its applicability in urban interchange planning and construction. Based on the observation of the traffic characteristics of the left entry ramp of Gumufeng Interchange in Chongqing, it is found that the ramp entrance is the main traffic conflict area, and there are a large number of traffic conflicts. This paper studies the blind area of the vehicle, discusses the blind area caused by the physical occlusion of the vehicle itself, the blind area caused by the position of the cab, and the difference of the blind area of the left and right side of the vehicle rearview mirror, and probes into the hidden dangers of the safety caused by the difference. On the basis of the hidden trouble of safety, the paper discusses the safety design of the left-in interchange ramp: the study of the blind area of the left and right side of the vehicle shows that there is a difference, but the code of our country does not reflect this difference. There is a concentrated traffic conflict at the ramp junction. On this basis, the safety design suggestions are put forward for each index of the entrance connection. Taking the left entry ramp of Gumofeng Interchange as an example, three different types of on-ramp connections are designed according to the specifications. Based on the actual traffic flow and traffic characteristics of Gumofeng Interchange, three kinds of entrance connections are simulated and analyzed by VISSIM software. The data of three forms of queue length and delay time under different traffic flow are taken as indicators to evaluate the degree of congestion, and then the degree of traffic conflict is judged.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U412.352

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