Research On Disaster-Adaptation Mechanism And Planning Response Of Comprehensive Evacuation-Shelter Space Based On CAS

With the intensification of global climate change and crustal movement,the frequency of various natural disasters has been obviously increased,and the number of catastrophic events has been enhanced too.At the same time,the rapid advance of industrialization and urbanization in China has led to the continuous growth of urban population.It means that a large number of urban population is,and will be,more exposed to natural disasters.Urban evacuation-shelter space is the second defense after engineering disaster-prevention facilities are damaged in disaster situation.It is to guarantee the safety of the population,as well as to hold rescue activities to assist the functioning of cities.Therefore,the planning and construction of evacuation-shelter space has become one of the key works of urban planning and disaster prevention."Disaster risk adaptation" is the fundamental goal of planning and construction of evacuation-shelter space.It means that under different disaster risk conditions,the key functions such as shelter,accommodation and rescue can be played reliably,so as to reduce or even avoid the population and related social and economic losses.However,when we look at the current evacuation-shelter space planning in cities,it seems that planners often follow the established experience,using solid-center planning techniques(means paying attention to static structure from a top-down view)to plan and design.The result is ignoring or avoiding the complex and vivid adaptation between evacuation-shelter space and disaster risk,making it difficult to propose accurate strategies adapting to disaster risk.What is disaster risk adaptation?How to adapt to disaster risk? This has become an urgent problem for the current evacuation-shelter space planning to consider and answer.The theory of Complex Adaptive System(CAS)was applied in this paper for the first time,to explore the internal operation mechanism and external planning response of "evacuation-shelter space adapting to disaster risk" system.Through the deduction from disaster-adaptation mechanism to planning,it can be used in the application of comprehensive evacuation-shelter space's disaster-adaptation planning.This helps break through the disaster-adaptation dilemma of existing evacuation-shelter space planning,and also makes up for the theoretical deficiency of existing researches on disaster adaptation.It is also expected to inspire other city's spaces to enrich their theory of disaster adaptation,and to improve corresponding planning.This paper is explored from basic platform construction,to overall discussion on disaster adaptation,to sub-topic discussion on disaster adaptation,and to planning application.The first part is to build a basic platform for this research.By sorting out and summarizing the development trends of "evacuation-shelter space","disaster risk" and "CAS theory",a basic platform for theoretical study and planning application is established.It shows this paper's breadth,depth and accuracy.To be specific,comprehensive evacuation-shelter space is as the main subject,which shows multi-disaster,multi-time,multi-meansure,multi-scale and multi-behavior expansion.The loss-type disaster risk is defined as the adapted object,which can be decomposed into hazard risk,exposure risk and sensitivity risk.The classic CAS theory is introduced,supplemented by derivative theory of social-ecology system and application routine of urban-space system.The second part is overall discussion on disaster adaptation of comprehensive evacuation-shelter space.Through the coupling analysis,it is proved that evacuation-shelter space adapting to disaster risk system belongs to CAS.In this proving process,a comprehensive theory of this disaster-adaptation system is established.It includes the spatial-complexity manifestation,disaster-adaptation requirements,composition of disaster-adaptation system,external characteristics of disaster-adaptation system,and internal mechanism of disaster-adaptation system.Through indicating that sustainable development is the core of adaptation,it is proposed the disaster-adaptation requirements of comprehensive evacuation-shelter space.Then,by setting up the functional framework of the internal mechanism to meet disaster-adaptation requirements,the operational mechanism model of the disaster-adaptation is established.The disaster-adaptation theory and mechanism model are converted into a disaster-adaptation concept and planning system.It includes establishing the general idea of disaster-adaptation planning,proposing new planning principles,advising a set of planning methods,reconstituting planning process and content,and put forwarding planning attributes and values.The third part is sub-topic discussion on disaster adaptation.Coastal city is one of the urban areas with the most vibrant social and economic activities,the most concentrated population and the most complicated disaster situation.It is very important for coastal cities to guarantee the population safety under the disaster situation and also to maintain the social and economic stability through comprehensive evacuation-shelter space's disaster-adaptation planning.According to the guidance of the disaster-adaptation planning system,it is divided into three special planning topics: "ensuring the safety of sites and environment,adapting to multiple-hazard risk","ensuring the effectiveness of emergency and accommodation,adapting to population-exposure risk","assisting the continuous operation and rapid recovery of cities,adapting to multiple-rescue sensitivity risk".Under each topic,firstly the main influential factors of disaster risk in coastal cities are analyzed,to determine the indexes of assessment and characteristics of spatial differentiation.According to the typical risk characteristics,the model of disaster-adaptation operational mechanism is concretized to form the action scenario within evacuation-shelter space.Based on this scenario,the form,configuration and layout strategies of evacuation-shelter space following the increase of disaster risk are proposed.They are carrying the autonomous action at the neighborhood level to the overall action at the city level.The fourth part is planning application taking a case of the core area of Tianjin Binhai New District(TBND).The disaster-adaptation strategies proposed in the third part are applied.The difference and details from TBND itself are discovered and solved,so as to guide the improvement of evacuation-shelter space planning in other coastal cities and also other kind of urban areas.Finally,a set of planning-safeguard strategies are suggested,which refers to multi-party planning participants,multi-level planning rights and responsibilities,and multi-step planning procedures.It can be used in the safeguard of compilation,implementation and use of comprehensive evacuation-shelter space's disaster-adaptation planning.