[en] Air-fluidization can be the origin of the long runout of gravitational flows involving fine particles such as ash. An excessive air pore pressure dramatically reduces the friction angle of the material as long as this pressure has not been dissipated, which occurs during the flow. This phenomenon can be modelled thanks to the 2D depth-averaged equations of mass and momentum conservation and an additional transport equation for basal pore pressure evolu- tion (Iverson and Denlinger, 2001). ln this contribution, we discuss the application of this model in relation to recent experimental results on air- fluidized flows by Roche et al. (2008) and Roche (2012). The experimental results were used to set a priori the value of the diffusion coefficient in the model, taking into account the diference of scale between the experiments and real-world applications. We also compare the model predictions against detailed observations of a well-documented historical event, the collapse of a fly-ash heap in Belgium (Stilmant et al., 2015). In particular, we analyse the influence of the different components of the model on the results (pore pressure dissipation vs. pore pressure generation). The diffusion coefficient which characterizes the dissipation of air pore pressure is found sufficiently low for maintaining a fluidized flow over hundreds of meters. The study concludes that an air-tluidization theory is consistent with the field observations. These findings are particularly interesting as they seem not in line with the mainstream acceptation in landslide modelling that air generally plays a secondary role (e.g., Legros, 2002).
Disciplines :
Civil engineering
Author, co-author :
Stilmant, Frédéric
Dewals, Benjamin ; Université de Liège > Département ArGEnCo > Hydraulics in Environmental and Civil Engineering
Archambeau, Pierre ; Université de Liège > Département ArGEnCo > HECE (Hydraulics in Environnemental and Civil Engineering)
Erpicum, Sébastien ; Université de Liège > Scientifiques attachés au Doyen (Sc.appliquées)
Pirotton, Michel ; Université de Liège > Département ArGEnCo > HECE (Hydraulics in Environnemental and Civil Engineering)
Language :
English
Title :
The contribution of air-fluidization to the mobility of rapid flowslides