Resilience of city underground infrastructure under multi-hazards impact: From structural level to network level

Underground infrastructure (UI) plays a great important role in the urbanization and modernization of megacities in the world. However, the intensive development of the UI during the past decades has posed great risks to the safety of city infrastructures under the impact of multi-hazards, especially with the condition of global climate change. In this paper, a general conceptualized framework to assess the resilience of UI in cities under multi-hazards impact is proposed. The urban tunnel system, e.g., metro tunnel, road tunnel etc., is selected as the typical underground infrastructure discussed with the emphasis both on the structural level in terms of mechanical behaviors and system level in terms of network efficiency. The hazards discussed in this paper include the natural hazards and human-related ones, with emphasis on earthquake, flood, and aggressive disturbances caused by human activities. After the general framework proposed for resilience of the structural and network behavior of the UI, two application examples are illustrated. The structural resilience of the shield tunnel under earthquake impact is analyzed by using the proposed resilience model, and the network resilience of the road tunnel system under the flood impact due to climate change is analyzed, respectively. The resilience enhancement by using the adaptive design strategy of real-time observational method is mathematically presented in this case. Some other practical engineering recovery measures are briefly discussed at the end of this application example. The findings in the application examples should be helpful to enhance the resilience-based design of the structural and network of tunnels from the component to the system level.