Ⅱ型大城市轨道交通系统选型

随着我国城镇化进程的加速,继特大、超大城市之后,众多II型大城市加入城市轨道交通的规划、建设行列。分析城市特征和国家政策,认为II型大城市更适合发展中运量的轨道交通系统。对比国内各类中运量轨道交通系统的发展现状,筛选出Lb型车、高地板C型车、70%低地板C型车、跨座式单轨共4种拥有独立路权、以交通功能为主的轨道交通系统供II型大城市选择。从服务水平、道路适应性、环境适应性、系统拓展能力4个方面分析备选系统与II型城市的适应性。认为Lb型车和高地板C型车的单位运输效率较高,Lb型车和70%低地板C型车的道路和环境适应能力较强,高地板C型车和70%低地板C型车网络化运营优势明显。以上4类系统能满足国内绝大多数II型大城市的交通需求,具体选型需结合城市特征和工程条件进一步分析。

Mode Selection of Urban Rapid Rail System in Type II Megacities

With the acceleration of China's urbanization,cities with an urban population of 1 to 3 million (Type Ⅱ megacities) have started to plan or build their urban rapid transit systems.Considering the commonly acknowledged population threshold of 3 million for developing mass urban transit and the medium-level ridership demand forecast of these cities,systems that provide a medium capacity (5,000-15,000 ridership per hour) and operate as arterial traffic corridors with exclusive fight-of-way are more suitable for Type Ⅱ megacities.Available systems include Type Lb vehicles,high-floor type C vehicles,70％ low-floor type C vehicles,and cross-saddle monorail.A suitability study of these four systems is conducted herein from the aspects of service level,adaptability to various roadway conditions,adaptability to different kinds of environment,and potential for network expansion.The following comparative advantages are also suggested:Type Lb and high-floor Type C vehicles have a higher capacity;Type Lb and 70％ low-floor Type C vehicles perform better in different roadway and environment conditions;and high-floor Type C and 70％ low-floor Type C vehicles are easier to operate in a network.In summary,the four types of medium-capacity urban rail transit system are potential options for most Type Ⅱ megacities.A further analysis on the mode selection should be made based on city shapes and specific engineering conditions.