Are real-world shallow landslides reproducible by physically-based models? Four test cases in the Laternser valley, Vorarlberg (Austria)

Abstract

In contrast to the complex nature of slope failures, physically-based slope stability models rely on simplified representations of landslide geometry. Depending on the modelling approach, landslide geometry is reduced to a slope-parallel layer of infinite length and width (e.g., the infinite slope stability model), a concatenation of rigid bodies (e.g., Janbu's model), or a 3D representation of the slope failure (e.g., Hovland's model). In this paper, the applicability of four slope stability models is tested at four shallow landslide sites where information on soil material and landslide geometry is available. Soil samples were collected in the field for conducting respective laboratory tests. Landslide geometry was extracted from pre-and post-event digital terrain models derived from airborne laser scanning. Results for fully saturated conditions suggest that a more complex representation of landslide geometry leads to increasingly stable conditions as predicted by the respective models. Using the maximum landslide depth and the median slope angle of the sliding surfaces, the infinite slope stability model correctly predicts slope failures for all test sites. Applying a 2D model for the slope failures, only two test sites are predicted to fail while the two other remain stable. Based on 3D models, none of the slope failures are predicted correctly. The differing results may be explained by the stabilizing effects of cohesion in shallower parts of the landslides. These parts are better represented in models which include a more detailed landslide geometry. Hence, comparing the results of the applied models, the infinite slope stability model generally yields a lower factor of safety due to the overestimation of landslide depth and volume. This simple approach is considered feasible for computing a regional overview of slope stability. For the local scale, more detailed studies including comprehensive material sampling and testing as well as regolith depth measurements are necessary.

Engineering-Geological Analysis of a Subaerial Landslide in Taan Fiord, Alaska

“…In the present study, the multi-temporal aerial radar data were used to reconstruct the slope morphology over time and to constrain the subsequent slope stability analyses via the limit equilibrium method. The applicability of remote-sensing data for landslide investigation has been confirmed in various studies [37][38][39][40][41][42][43]. The aim of this study is to gain a better understanding of the landslide process, and of which factors or external triggers may have induced the slope failure.…”

iHydroSlide3D v1.0: an advanced hydrological-geotechnical model for hydrological simulation and three-dimensional landslide prediction

“…More recently, progress has been made in a more sophisticated software r.slope.stability (Mergili et al, 2014a;Mergili et al, 2014b) that have the capacity to perform on a regional scale via a parallel computational technique. More importantly, the 3D slope-stability model demonstrates to be effective on both shallow and deep landslides, thus better behaves as a robust geotechnical tool and has a potential for wide applications (Zieher et al, 2017;Palacio Cordoba et al, 2020).…”

Improving Spatial Landslide Prediction with 3D Slope Stability Analysis and Genetic Algorithm Optimization: Application to the Oltrepò Pavese

“…The great majority of landslide models used infinite slope stability analysis [21,22,[30][31][32][33][34][35][36], according to which the failure of each cell is assumed to be independent of the other ones in the catchment, resulting in unstable areas that have low connectivity, which are thus quite unrealistic. Hence, there is an increasing scientific interest towards the development of software that implements three-dimensional slope stability analysis [37][38][39][40][41][42][43].…”