基于数值模拟的阶梯水流中行人安全撤离研究(英文)

Assessment of the safe evacuation of people walking through flooding staircases based on numerical simulation

目的:研究不同形式阶梯水流中被困人员的安全撤离,为地下空间水侵灾害脆弱性评价及防灾避灾提供参考。方法:根据试验结果和数值模型的相关理论构建数值模型,验证数值模拟阶梯水流流场的可靠性和合理性,并基于数值模型的灵活性和可变性,模拟休息平台、阶梯坡度和阶梯形态对水流流场的影响,据此对有无休息平台、不同阶梯坡度和不同阶梯形态下阶梯水流流态、流速分布以及对被困人员的安全撤离的影响进行深入分析。结论:中间休息平台的存在增加了被困人员撤离的风险;阶梯坡度对阶梯上水流的水力特性影响很小;L型阶梯中间休息平台有利于减小平台下游撤离风险,被困人员可以优先选择L型阶梯或者不含休息平台的直线型阶梯撤离。

A numerical model was developed to evaluate the possibility of people walking in a flooding flow on a staircase with rest platforms. Commercial software was used and validated by experimental data for flows on staircases and stepped spillways. The effects of the rest platform, the staircase slope, and the staircase pattern on the flooding flow characteristics are discussed. A comparison of staircases with or without rest platforms shows that the flow velocity increases significantly downstream of the rest platform on a straight-run type, which would have negative effects on the safe evacuation of people walking through a flooding staircase. The slope of the staircase, ranging from 26.6° to 30°, has less effect on safe evacuation. A comparison of flows on straight-rim （with or without rest platforms）, 90°-turn and 180°-turn staircases （with rest platforms） shows that the rest platforms on the latter two staircases could induce a redistribution of the flow field on the rest platform and downstream. The distribution of evacuation indicators along the longitudinal planes of those staircases indicates that a 90°-turn staircase or a straight staircase without rest platform would be the first choice for trapped people evacuating from underground spaces.