极端环境公路网络运输能力韧性研究

李成谦

摘要

公路运输系统安全平稳运行对国家安全以及经济社会发展具有重大意义。本文以极端环境下公路运输系统为对象，研究公路网络在频发灾害下长期运输能力的受损与恢复过程，分析影响公路网络运输能力的关键瓶颈，提出韧性优化的有效措施。具体研究内容如下：

（1）极端环境与非极端环境下公路网络韧性的差异。现阶段的路网韧性分析方法大部分面向非极端环境提出，但极端环境下公路网络设施面临着更严峻的生存性和可持续性考验。据此，本文梳理现阶段基础设施韧性研究的相关文献，提出极端环境下路网韧性的关键特征，分析在多灾种、高强度、高频率的灾害冲击下公路网络设施功能水平的动态变化机理，建立其分析研究的基础框架。

（2）极端环境下公路网络失效风险。本文指出公路极端环境的典型环境特征、灾害特点以及致灾因素：一方面，利用地震危险性概率分析方法研究地震灾害下路网的失效风险，通过生成震害场景、分析场地运动特征、评估公路设施易损性等步骤计算公路设施的失效风险；另一方面，利用荷载——抗力推断方法分析山地灾害的危险性，结合公路设施结构类别、公路等级等参数推断其抗灾能力，评估山地灾害下公路设施的受损状态。

（3）极端环境下公路网络长期运行与恢复仿真。根据公路网络的失效风险，本文进一步利用蒙特卡洛仿真方法预估各类灾害事件的发生位置、时间以及恢复时长，并模拟生成各类灾害事件；再建立受灾路段的抢修恢复仿真模型，根据受灾情况、恢复资源以及路段重要性来分配安排各个受灾路段的应急抢修顺序；最后，提出基于用户均衡原理的受损路网交通流分配方法，构建交通流分配仿真模型，评估受损路网的社会功能价值。

（4）公路网络韧性分析与优化策略。根据极端环境下公路网络长期运行的服务水平，本文提出路网运输能力韧性的评价指标，从流动性、可达性以及人员伤亡情况综合评估路网在极端环境下提供服务质量的稳定性程度；接着，深入挖掘交通系统的韧性优化潜力，指出灾后交通运输保障的关键点，分析各类韧性优化措施的适用性条件，构建运输能力韧性优化模型，提升极端环境路网在未来长期运行过程中的运输保通能力。

最后，本文对川藏路网的长期运行韧性进行深入分析，通过路网失效风险评估、受损路网应急抢修过程仿真、路网交通分配仿真等步骤，对比川藏路网在正常状态下与处于频发灾害下运输能力差异，提出川藏路网韧性提升的优化策略。

关键词：极端环境；公路网络；韧性；运输能力；社会技术系统

Abstract

The safe and stable operation of the road transport system is of great significance to national security and economic and social development. This dissertation focuses on the long-term performance dynamics of the road transport system resulting from frequent damage and recovery processes in an extreme environment. It identifies key bottlenecks in road network capacity and provides effective resilience optimization measures. The specific research contents are as follows:

(1) The distinctions between extreme-environment resilience and non-extreme environment resilience are studied. At present, most existing research on road network resilience are designed for the non-extreme environment. In an extreme environment, roadway facilities face a more stringent test of survivability and durability. It is necessary to analyze the functional dynamics of road network facilities under the impact of multi-hazard, high-intensity, and high-frequency disasters. This dissertation explores existing research literature on infrastructure resilience, presents key features of road network resilience in an extreme environment, and provides a comprehensive framework for the following analysis.

(2) The failure risk of the road network in an extreme environment is studied. This dissertation points out the extreme-environment chracteristics of the road network, including the disaster characteristics and disaster causing factors. On the one hand, the probabilistic seismic hazard analysis method is introduced to analyze the seismic failure risk of the road network by earthquake disaster scenario generation, site movement characteristics analysis, and facility fragility evaluation. On the other hand, the mountain disaster hazards are analyzed according to the environmental risk factors, and the disaster resistance of the roadway facilities is evaluated based on the facility parameters, such as the structural types, traffic capacity, etc. The damage states of roadway facilities are predicted using the load-resistance interference method.

(3) The simulation of the long-term operation and recovery process of the road network in an extreme environment is studied. Based on the failure risk of the road network, this dissertation uses the Monte Carlo simulation method to predict the occurrence location, time, and recovery time of various kinds of disaster events. The model to simulate the repair and emergency recovery of faulty road links is then established. According to the disaster situation, the repair sequences of failed road links are determined by the availability of recovery resources and the importance of each road link. Finally, a traffic assignment model is established to study the traffic flow distribution of the damaged road network based on the principle of user equilibrium. Its purpose is to evaluate the social functionality of the damaged road network.

(4) The resilience analysis methodology and the road network optimization strategy are studied. Based on the service level of road network during the long-term operation in an extreme environment, this dissertation presents the indices for assessing the resilience of the transport capacity of a road network in terms of mobility, accessibility and victims. It deeply taps into the resilience optimization potential of the transportation system, points out the key points for post-disaster transportation service support, studies the applicability of kinds of resilience optimization measures, and develops a resilience optimization model to strengthen the transport capacity of the road network under an extreme environment during the future long-term operation.

By combining the above methods, including failure risk analysis, emergency repair and traffic assignment simulation, a resilience analysis framework for the road network in an extreme environment is formulated. The proposed framework is applied to the Sichuan-Tibet road network, and the resilience optimization strategy is presented by comparing the network capacity in perfect operation with that in damaged states.

Keywords: Extreme environment；Road network；Resilience；Transportation capacity；Sociotechnical system