多层及低层居住街区空间形态对避震疏散安全可达效能的影响机制与优化方法

The promotion of space's earthquake evacuation capacity in the mid-rise and low-rise residential blocks is the key and difficult point in the construction of urban disaster-prevent. It increasingly emphasizes the systemic integration of capacity arrangement, structural layout, space form and technical facilities. At present, in the deepening and implementation of the related planning, the overall control and efficient optimization of the three-dimensional spatial form in the block lacks scientific theoretical basis and effective design method. It is difficult to ensure the full play of space evacuation efficiency. This topic combines theories and methods in the fields of earthquake evacuation, risk assessment and spatial network analysis with the primary survey data, aims at spatial influence of the risk factors of collapse, fire and falling objects of buildings during the earthquake, based on the cumulative process of evacuation distance and safety risk from the local to the whole in pedestrian emergency evacuation, focuses on the impact of the combination space form of building, path and open space on safety and accessibility efficiency, carries out model simulation, quantitative evaluation and mechanism analysis fitting in with the spatial-temporal rule of evacuation, and construct the optimization method of the multi scene targets. The research findings will provide a scientific and quantitative theoretical basis and design method for the optimization and control of spatial form of the mid-rise and low-rise residential blocks for earthquake evacuation capacity, and it plays an important role in planning and design control of the block space.

多层及低层居住街区空间的避震疏散效能提升是城市防灾建设的重点与难点，越来越强调容量配置、结构布局、空间形态与技术设施的系统整合。目前，在相关规划的落实深化中，街区建筑环境三维空间形态的整体控制与高效优化缺乏科学的理论依据与有效的设计方法，难以保证空间避震疏散效能的充分发挥。本项目结合避震疏散、风险评价和空间网络分析等领域的理论与方法，以足量一手调研资料为基础，针对建筑承载的震时倒塌、出火和坠物风险要素的空间影响，基于步行紧急避震疏散行动中疏散距离与安全风险自局部至整体的累积过程，重点研究建筑、道路路径与开放空间的组合形态对于疏散安全可达效能的影响，实现切合避震疏散行动时空规律的形态-效能影响的模型模拟、量化评价与机制解析，建构多情景目标的优化方法。课题成果将为多层、低层居住街区避震疏散的空间形态优化控制提供科学量化的理论依据与设计方法，对街区空间防震安全的设计改造及规划管控具有重要作用。

通过空间形态的优化控制提升空间环境的避震疏散能力，是多层与低层居住街区防灾建设与改造的重要途径，但尚未系统认知三维空间形态对于疏散可达及安全效能的影响过程和影响机制，相对缺乏具有科学依据的评价与优化方法。本研究梳理多层与低层居住街区避震疏散时空特征、主要效能要素和空间影响要素，针对步行紧急避震疏散行动中疏散距离与安全风险自局部至整体的累积过程，建立概率计算模拟模型。通过模型与网络分析技术的结合运用，针对不同形态类型的街区，进行疏散可达和安全效能评价，分析街区用地形态、避难场所位置、疏散路径及其网络形态、建筑高度布局等要素及组合关系的效能影响。研究认为，空间形态要素不同程度的影响疏散距离和安全风险，沿疏散路径与网络不断累积，空间形态要素的组合使不同层次的累积效果相互关联，导致街区整体疏散效能、建筑疏散效能及其空间分布产生差异。本研究针对可达、安全及其综合效能提升，从整体到局部空间总结提出效能提升的形态优化方法，并结合设计项目进行应用层面的探讨。本研究为多层及低层居住街区面向避震疏散的空间形态优化及设计改造，提供基础性的理论视角和方法依据。总体上，本研究在基础研究、计算模拟、模型建构、效能与空间形态评价、影响机制、优化方法方面取得成果，完成预期研究目标。