Effects of river flow velocity on the formation of landslide dams

A Numerical Study of the Critical Threshold for Landslide Dam Formation Considering Landslide and River Dynamics

“…Several works have demonstrated that the formation of a landslide dam is determined by the erosive capacity of the river and the deposition rate of the landslide, both of which are related to the landslide and river discharges, particle diameter and river slope (Yan et al, 2009;Zhao et al, 2017;Chen et al, 2019a). Based on experiments, Chen et al (2019a) suggest that landslide-generated dams form once the ratio of the erosion rate of river flow to the deposition rate of the landslide exceeds a threshold value. As a matter of fact, these rates represent the discharges of eroded mass and intruding landslide per unit time and therefore, the dimensionless critical discharge can be written in the form of discharge as…”

“…Numerous studies have demonstrated that geomorphological features Korup (2004); Fan et al (2012); Chen and Chang (2016); Chen et al (2021) and hydrological conditions Zhao et al (2017); Chen et al (2019a); Liao et al (2019) jointly determine whether a landslide dam can be formed. Based on these studies, the following three conditions are essentially mandatory to form a landslide dam: first, the landslide needs to cross the river channel; second, the erosive rate of river flow must be smaller than the depositional rate of the landslide; and three, the thickness of landslide deposits in the river channel must be greater than the water depth (Fan et al, 2014;Chen and Chang, 2016;Chen et al, 2019b).…”

“…The erosive capacity of the river and the deposition rate of the landslide determine whether a dam can be formed when a landslide reaches a river. The former factor is significantly influenced by river conditions, including flow depth, flow velocity and river slope (Whipple et al, 1998;Carroll et al, 2004;Zhang et al, 2009;Chen et al, 2019a). The latter factor depends mostly on the characteristics, (e.g.…”

“…Although some studies have investigated the mechanism of granular deposition in fluid and its influence on dam formation Shan and Zhao (2014); Zhao et al (2019); Li et al (2020), they do not consider the impacts of the erosive capacity of river flow on dam formation. Recently, Chen et al (2019a) suggested a critical threshold that reflects the influence of river erosive capacity on dam formation in a quantitative way. However, one drawback of this threshold is that it does not consider the dynamic characteristics of the landslide.…”

“…Because only average river erosive capacity can be observed in the experiment performed by Chen et al (2019a), there are no way to quantify dynamic processes and dynamic change of different enter river direction (between the river channel and landslide movement direction). Therefore, we need to use numerical simulation to clarify the dynamic process of landslide movement, landslide dam formation and river erosive capacity.…”