An Analysis of Factors Affecting Flowslide Deposit Morphology Using Taguchi Method

Abstract

Flowslides, as one type of landslides, are becoming a research hotspot due to their high speed and long runout distance, which can cause tremendous damage and economic loss. The scale of damage and deposit morphology of flowslide is closely related to factors like deposit volume, slope height, and slope angle. In order to assess the influence of these factors, a sandbox apparatus is developed, and the Taguchi method is used to design an experimental scheme to analyze the results of factors affecting the deposit morphology of flowslide. The results show that the factor that has the greatest impact on flowslide deposit morphology is slope angle, followed by the influence of volume and slope height. As slope angle increases, the maximum width, maximum length, area, and length-width ratio of the deposit first increase and then decrease. In addition, there should be a critical angle in the changes of deposit morphology that is between 60° and 70° under the experimental conditions. When the volume is 5.4 × 10−3 m3, the slope angle is 70°, the slope height is 0.90 m, and the changes of deposit morphology of the flowslide are the largest. In this study, considering the slope angle as a single variable, there is a single upheaval for a slope angle of 40° and 50° and a double upheaval at 60° and 70°. The formation mechanism of the upheaval is analyzed based on the Mohr-Coulomb criterion and considered properties of the material. The apparent friction coefficient of a flowslide is spatially and lithologically different and increases nonlinearly as the slope angle increases. The initial benchmark of the slope angle and apparent friction coefficient curve are affected by the friction coefficient of the material; the position of the inflection point at which the curve increases rapidly is affected by the coefficient of velocity restitution.

Influences of Slope Angle on Propagation and Deposition of Laboratory Landslides

“…The reason why the sliding mass spreads radially is because its bottom portion carries water during propagation. The double-upheaval morphology appeared on the surfaces of deposits at high slope angles, which is consistent with previous physical modelling studies (Roche et al, 2011a;Duan et al, 2020;Lajeunesse et al, 2005;Lajeunesse et al, 2006;Lajeunesse et al, 2004) and field investigations (Hutchinson, 2002;Quantin et al, 2004). This morphology was observed by Roche 455 et al (2011a) in a cylinder experiment (where sand was filled into a cylinder that was lifted up rapidly to release the sand), who proposed that it is caused by the wave formed by the impact of later sand to the sand reached already on the horizontal plate.…”

“…Of course, the difference in the apparent friction coefficients of these landslides is not only caused by differences in slope angle but also by differences in volume and the type of sliding mass. However, the slope angle has a more significant effect on the apparent friction coefficient (Duan et al, 2020;Huang and Liu, 2009).…”

The Motion and Range of Landslides According to Their Height

“…There are some differences in the names and formulas used to describe this ratio (Scheidegger 1973;Staron 2008;Lucas, Mangeney, and Ampuero 2014;Crosta et al, 2015). It has been referred to as the "Fahrboschung" (Evans and Clague 1994;Geertsema et al, 2006;Hungr 2006), "reach angle" (Scheidegger 1973;Corominas 1996) "effective friction coefficient" (Staron 2008), and "apparent friction coefficient" (Scheidegger 1973;Bouchut et al, 2015;Duan et al, 2020;Yang et al, 2018;Staron 2008;Magnarini et al, 2019;Wang, Sassa, and Fukuoka 2003;Yang et al, 2011;Legros 2002). By associating H/L with the mass of the sliding body, it has been found that a larger sliding mass body results in a lower H/L and stronger landslide movement ability.…”

“…Experiments can help to understand the movement mechanism involved in particle flows and have been widely used in research on the movement of geological hazards in recent years. They can also evaluate relevant physical parameters to improve slip distance predictions and verify numerical models (Duan et al, 2020;Iverson, George, and Logan 2016;Ng et al, 2017;H. Q. Yang et al, 2018;Y.-F. Wang et al, 2016).…”

Impact‐Induced Liquefaction Mechanism of Sandy Silt at Different Saturations

“…When the apparent friction angle is less than the internal friction angle of the soil, it indicates that there may be an effect of reducing frictional resistance during sliding, such as the generation of pore water pressure (liquefaction) [24]. e value of the apparent friction angle of the Miaodian landslide is 10.9° [2,25,26], and the internal friction angle of the saturated loess is about 30° [24]. erefore, it can be suggested that there is a possibility of liquefaction during the sliding process of this landslide.…”