拥挤交通网络中关键应急避难场所识别模型与求解

Model and algorithm for identifying critical emergency shelters in congested traffic networks

识别关键应急避难场所是抵御设施失效和服务功能丧失对应急服务系统所构成损害的重要手段。以往基于设施中断模型的关键应急避难场所识别问题的处理,忽略了疏散时交通网络会处于拥挤状态,道路行程阻抗与交通网络流量相关联这一现象。针对拥挤交通网络中关键应急避难场所识别问题,假设疏散者能够选择最近的应急避难场所,并可根据交通拥挤状况选择最短路径到达,构建基于交通网络流均衡约束的应急避难场所中断单层优化模型。将部分非线性约束转化为一定条件下的线性约束,通过CPLEX优化软件进行求解。算例路网计算表明,较非拥挤交通网络,拥挤条件下关键应急避难场所中断对系统造成的影响被低估了64.4%。

Identifying critical evacuation shelters is an important strategy to resist the resulting impacts for emergency service systems due to interdiction of shelters and their services. However,the preceding critical shelters identification problem based on facility interdiction models fails to perceive the phenomenon that the travel impedance interrelates with network flows in congested traffic networks during evacuation. In order to identify the critical shelters in congested traffic networks, a single level shelter interdiction model employing traffic user equilibrium approach is formulated,hypothesizing each evacuee is able to choose the shortest path to the closest shelter from the demand node. Partial nonlinear constraints are converted into linear constraints. This model is solved by using CPLEX optimization tools. A case study shows that the impact caused by critical evacuation shelters interdiction in the congested traffic network is underestimated by 64. 4% in comparison with that in the uncongested traffic network.