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Debris flow: its intensity and damage caused to the built environment

Miteva Tanja Prina Howald Erika
Articolo Immagine
GEAM N. 165/2022

Articolo Open Access


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Debris flow events are known today as one of the most dangerous natural hazard events due to the elevated impact pressures they can reach. Depending on its intensity, a debris flow has the capacity to flatten forests and carry along the tree trunks, to completely demolish buildings and consequently to create a great risk to human life. However, the damage caused to a building by a debris flow also depends on the structural resistance of the building, orchestrated by many other indicators such as the construction material, the number of floors, the orientation of the building, the maintenance levels, etc. As a result, a historical survey was conducted in this work, studying the different types of building structures and the damage they suffered due to debris flows. Furthermore, the damage to the buildings as such is a parameter that can be assessed by various methods. What is certain is that the higher the intensity of the debris flow, the greater the damage to the built environment and thus the greater the risk to human life. In order to understand better this natural process and reduce the risk of human and economic losses a large amount of research has been done in the field regarding the process of debris flow itself. Nevertheless, the assessment of debris flow intensity remains a task quite difficult to accomplish. The latter is due to various reasons; for instance, on one hand, there is the versatility of debris flow in terms of the origins of the materials that compose it, the height and velocity it can reach and on the other hand, the difficulty of determining these parameters. These challenges have been at the origin of many different approaches developed and used throughout the years in order to assess debris flow intensity. In this paper some of the existing approaches established in the quest of debris flow intensity assessment will be presented and evaluated. The main objectives of this paper are first the definition of the main types of structures vulnerable to debris flows, then the suggestion of a methodology to assess the damage caused to buildings by a debris flow and finally the proposal of a general approach, commonly implementable, for the assessment of the intensity of debris flows.

Keywords: Debris flow; Building vulnerability; Building damage; Impact pressure.