The Effect of Bedrock Topography on Timing and Location of Landslide Initiation Using the Local Factor of Safety Concept

Shirin Moradi,Holger Class,Johan Huisman,Harry Vereecken

doi:10.3390/w10101290

Shirin Moradi, Holger Class + Show 2 more

Open Access

https://doi.org/10.3390/w10101290

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Journal: Water	Publication Date: Sep 20, 2018
Citations: 10	License type: CC BY 4.0

Affiliation: Forschungszentrum Jülich, University of Stuttgart

Abstract

Bedrock topography is known to affect subsurface water flow and thus the spatial distribution of pore water pressure, which is a key factor for determining slope stability. Therefore, the aim of this study is to investigate the effect of bedrock topography on the timing and location of landslide initiation using 2D and 3D simulations with a hydromechanical model and the Local Factor of Safety (LFS) method. A set of synthetic modeling experiments was performed where water flow and slope stability were simulated for 2D and 3D slopes with layers of variable thickness and hydraulic parameters. In particular, the spatial and temporal development of water content, pore water pressure, and the resulting LFS were analyzed. The results showed that the consideration of variable bedrock topography can have a significant effect on slope stability and that this effect is highly dependent on the intensity of the event rainfall. In addition, it was found that the consideration of 3D water flow may either increase or decrease the predicted stability depending on how bedrock topography affected the redistribution of infiltrated water.

Highlights

Landslides are widely considered to be an important erosion process [1,2,3,4,5,6]
The initiation of landslides is frequently related to rainfall and the influence of hydrological processes on soil mechanics and slope stability has been known for a long time [22]
The overall aim of this study is to investigate the effect of bedrock topography and soil layering on the spatial and temporal initiation and development of failure-prone areas using

Summary

Introduction

Landslides are widely considered to be an important erosion process [1,2,3,4,5,6]. Typically, translational slope failures that involve the upper few meters of unconsolidated superficial materials (i.e., soil or regolith) dominate sediment transport in hillslope environments [7]. Any factor that increases the stress or reduces the soil strength can trigger landslides [12]. The stability of slopes is affected by a wide range of factors such as surface topography [13,14], the internal friction angle [14], the cohesion of soil and roots [13,15,16], rainfall intensity [17], the soil initial condition [18], spatial patterns of soil wetness (e.g., macro-permeability and local hydrology) [19,20], and persisting positive pore water pressure as well as high water saturation [15,21]. The initiation of landslides is frequently related to rainfall and the influence of hydrological processes on soil mechanics and slope stability has been known for a long time [22].

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Conclusion