Due to constraint land, more and more high-rise buildings are built in cities. It is unsafe to evacuate by elevators, thus stairs has an important impact on evacuation. So it is of great significance to analyze evacuation in stairwell. However, few researchers could reproduce occupant arc trajectories at the mid-landing in stairwell. A stair model based on circle-based floor field (Stair Circle-based Optimal Step Model — SCOSM) is proposed to investigate human performance in stairwell, in which occupants could make a turn with a certain point and move like as an arc. SCOSM is testified to validate by comparing simulated results and experimental datasets in respect of whole evacuation time and net person for each floor. What is more, the model is used to study the effect of interface. It is found when width of stairs (S1) is equal to the width of mid-landing (S2), pedestrian flow is dominated by the width of mid-landing (S2). As for effect of stair geometry on merging, structures except scenario a are inclined to preferring occupants from floor. The studies in this paper could help offer engineers a technical foundation for codes and fire protection design.

由于土地的限制，城市中建造了越来越多的高层建筑。用电梯疏散是不安全的，因此楼梯对疏散有重要影响。因此，对楼梯间的疏散进行分析具有重要意义。但是，很少有研究人员能够再现楼梯间中部着陆点的乘员弧形轨迹。为了研究人类在楼梯间的性能，提出了一种基于圆形地板场的楼梯模型（基于楼梯圆形的最佳台阶模型— SCOSM），在该模型中，乘员可以向某个点转弯并像弧线一样移动。通过比较模拟结果和实验数据集（关于每个楼层的整体疏散时间和净人），SCOSM进行了验证。此外，该模型用于研究界面的效果。发现当楼梯的宽度（S1）等于中间着陆的宽度（S2）时，行人流量受中间着陆的宽度（S2）支配。至于楼梯几何形状对合并的影响，除方案a外的其他结构倾向于从地板上选择居住者。本文的研究可以为工程师提供规范和防火设计的技术基础。