Revealing the Importance of Capillary and Collisional Stresses on Soil Bed Erosion Induced by Debris Flows

Abstract

Debris flows (Hungr et al., 2014) surge downslope at high velocities under the influence of gravity. Such flows may cause fatalities (Froude & Petley, 2018) and damage to infrastructure (Jakob et al., 2012). The destructive potential of these flows is enhanced by their ability to erode bed material along their flow paths (Hungr et al., 2005). Thus, reliable predictions of erosion are central to the delineation of debris flow hazards. Despite a multitude of erosion models proposed in the literature (Cao et al., 2004; Fraccarollo & Capart, 2002; McDougall & Hungr, 2005; Medina et al., 2008; Pirulli & Pastor, 2012; Sovilla et al., 2006; Sutherland, 1967; Takahashi, 1978), erosion remains one of the most difficult momentum exchange processes to predict (Hungr et al., 2005; Iverson, 2012). Thus, fundamental research is essential to improve our understanding of the erosion process.