Landslide-generated impulse waves

Abstract

Las olas generadas por deslizamientos son una amenaza para las personas y la infraestructura cercana a los cuerpos de agua. Entre los modelos que se han utilizado para predecir las características de la ola generada, se encuentra el depth averaged model, implementado en r.avaflow 2.3. En este trabajo se reconstruyen en r.avaflow los experimentos de laboratorio realizados por Miller et al. (2017) y por Bullard (2018) para evaluar la exactitud del modelo físico y numérico implementado en el programa. Se encontró que las características de la ola y del deslizamiento son similares entre las observaciones experimentales y los resultados numéricos, especialmente en el near-field y para bajas profundidades del reservorio. Además, se presentan los resultados experimentales de colapsos de columnas granulares planares. Las observaciones que se realizaron son, primero, que el máximo valle de la landward wave disminuye con la inmersión de la columna y, segundo, que la posición donde se produce este máximo valle es constante para todos los valores de inmersión.

Landslide generated waves, often refered as tsunamis in coastal engenieering, are a latent hazard to people and infrastructure near water bodies in mountainous areas. Therefore, models that allow for predictions of the wave behavior have been developed in order to perform risk assessments. A depth averaged model is employed to model the motion of multiphase mass flows, including the possibility of the landslide to interact with a reservoir. In this work, the laboratory experiments made by Miller et al. (2017) and Bullard (2018) of subaerial flows impacting a water reservoir are recreated with r.avaow 2.3, exploring the similarities between the experimental and the numerical results. Landslide, wave, and deposit characteristics are compared. The numerical results are in good agreement with the experimental results particularly in the near-field and for shallow still water depths. The virtual mass arise as an important component to be considered in the mass flow model as it can take substantial larger values than the drag component. Additionally, a series of laboratory experiments are performed to provide the first insights in the relationship between landward waves and column level of submergence. The maximum landward wave trough shows an inverse relation with the columns submergence, and the position where the maximum landward wave trough is generated shows a constant relation with the submergence ratio.