Flood-related hazard criteria during the human evacuation of underground spaces through stairs: a state-of-the-art review

This state-of-the-art review presents a comprehensive analysis of the available literature that focuses on defining instability criteria for hazard assessment during human evacuation of underground flooded stairs. Due to the increasing urbanisation trend and more recurrent flood events worldwide that are affecting exposed habitable areas like underground spaces. The studies in this research are outlined in three main groups: theoretical, experimental campaigns and numerical approaches.

Several methods for defining specific criteria were found, most of these criteria were described as a function of water depth (D) alone or in combination with velocity (V) highlighting the importance of these two water-related parameters for flood-related hazard evaluation. Succinctly, the most relevant findings and limitations of these studies are discussed and summarised in tables. A comparison with other flood-related hazard criteria in plain and mild-slope areas is presented. Finally, potential future investigation lines are proposed. Thus, this state-of-the-art review could offer a comprehensive overview of the topic and stimulate new exploratory studies in this research field yielding valuable insights that can be easily transmitted to stakeholders or non-experts and foster urban resilience during floods.