A steady-state analytical slope stability model for complex hillslopes

2008 ◽  
Vol 22 (4) ◽  
pp. 546-553 ◽  
Author(s):  
Ali Talebi ◽  
Peter A. Troch ◽  
Remko Uijlenhoet
Keyword(s):  
Steady State ◽  
Slope Stability ◽  
Stability Model

scholarly journals Soil moisture storage and hillslope stability

2007 ◽  
Vol 7 (5) ◽  
pp. 523-534 ◽  
Author(s):  
A. Talebi ◽  
R. Uijlenhoet ◽  
P. A. Troch
Keyword(s):  
Soil Moisture ◽  
Steady State ◽  
Slope Stability ◽  
Safety Factor ◽  
Unsaturated Zone ◽  
Soil Depth ◽  
Critical Role ◽  
Infinite Slope ◽  
Stability Model ◽  
Hillslope Stability

Abstract. Recently, we presented a steady-state analytical hillslope stability model to study rain-induced shallow landslides. This model is based on kinematic wave dynamics of saturated subsurface storage and the infinite slope stability assumption. Here we apply the model to investigate the effect of neglecting the unsaturated storage on the assessment of slope stability in the steady-state hydrology. For that purpose we extend the hydrological model to compute the soil pore pressure distribution over the entire flow domain. We also apply this model for hillslopes with non-constant soil depth to compare the stability of different hillslopes and to find the critical slip surface in hillslopes with different geometric characteristics. In order to do this, we incorporate more complex approaches to compute slope stability (Janbu's non-circular method and Bishop's simplified method) in the steady-state analytical hillslope stability model. We compare the safety factor (FS) derived from the infinite slope stability method and the more complex approach for two cases: with and without the soil moisture profile in the unsaturated zone. We apply this extended hillslope stability model to nine characteristic hillslope types with three different profile curvatures (concave, straight, convex) and three different plan shapes (convergent, parallel, divergent). Overall, we find that unsaturated zone storage does not play a critical role in determining the factor of safety for shallow and deep landslides. As a result, the effect of the unsaturated zone storage on slope stability can be neglected in the steady-state hydrology and one can assume the same bulk specific weight below and above the water table. We find that steep slopes with concave profile and convergent plan shape have the least stability. We also demonstrate that in hillslopes with non-constant soil depth (possible deep landslides), the ones with convex profiles and convergent plan shapes have slip surfaces with the minimum safety factor near the outlet region. In general, when plan shape changes from divergent to convergent, stability decreases for all length profiles. Finally, we show that the applied slope stability methods and steady-state hydrology model based on the relative saturated storage can be used safely to investigate the relation between hillslope geometry and hillslope stability.

scholarly journals A method for predicting the factor of safety of an infinite slope based on the depth ratio of the wetting front

2015 ◽  
Vol 3 (1) ◽  
pp. 791-836 ◽  
Author(s):  
B.-G. Chae ◽  
J.-H. Lee ◽  
H.-J. Park ◽  
J. Choi
Keyword(s):  
Steady State ◽  
Slope Stability ◽  
Unsaturated Soil ◽  
Landslide Susceptibility ◽  
Shallow Landslides ◽  
Rainfall Infiltration ◽  
Wetting Front ◽  
Operating Characteristics ◽  
Infinite Slope ◽  
Depth Ratio

Abstract. Most landslides in Korea are classified as shallow landslides with an average depth of less than 2 m. These shallow landslides are associated with the advance of a wetting front in the unsaturated soil due to rainfall infiltration, which results in an increase in water content and a reduction in the matric suction in the soil. Therefore, this study presents a modified equation of infinite slope stability analysis based on the concept of the saturation depth ratio to analyze the slope stability change associated with the rainfall on a slope. A rainfall infiltration test in unsaturated soil was performed using a column to develop an understanding of the effect of the saturation depth ratio following rainfall infiltration. The results indicated that the rainfall infiltration velocity due to the increase in rainfall in the soil layer was faster when the rainfall intensity increased. In addition, the rainfall infiltration velocity tends to decrease with increases in the unit weight of soil. The proposed model was applied to assess its feasibility and to develop a regional landslide susceptibility map using a Geographic Information System (GIS). For that purpose, the spatial databases for input parameters were constructed and landslide locations were obtained. In order to validate the proposed approach, the results of the proposed approach were compared with the landslide inventory using ROC (Receiver Operating Characteristics) graph. In addition, the results of the proposed approach were compared with the previous approach used steady state hydrological model. Consequently, the approach proposed in this study displayed satisfactory performance in classifying landslide susceptibility and showed better performance than the steady state approach.

scholarly journals Does parameterization influence the performance of slope stability model results? A case study in Rio de Janeiro, Brazil

Landslides ◽  
2016 ◽  
Vol 14 (4) ◽  
pp. 1389-1401 ◽  
Author(s):  
Carolina de Lima Neves Seefelder ◽  
Sérgio Koide ◽  
Martin Mergili
Keyword(s):  
Slope Stability ◽  
Rio De Janeiro ◽  
Stability Model

scholarly journals Probabilistic landslide susceptibility analysis in tropical mountainous terrain using the physically based r.slope.stability model

2019 ◽  
Author(s):  
Johnnatan Palacio Cordoba ◽  
Martin Mergili ◽  
Edier Aristizábal
Keyword(s):  
Slope Stability ◽  
Landslide Susceptibility ◽  
Confusion Matrix ◽  
Hazard Mapping ◽  
Infinite Slope ◽  
Susceptibility Analysis ◽  
Colombian Andes ◽  
Infinite Slope Stability Model ◽  
Stability Model ◽  
Physically Based

Abstract. Landslides triggered by rainfall are very common phenomena in complex tropical environments such as the Colombian Andes, one of the regions most affected by landslides every year. Currently in Colombia, physically based methods for landslide hazard mapping are mandatory for land use planning in urban areas. In this work, we perform probabilistic analyses with r.slope.stability, a spatially distributed, physically based model for landslide susceptibility analysis, available as an open-source tool coupled to GRASS GIS. This model considers alternatively the infinite slope stability model or the 2.5D geometry of shallow planar and deep-seated landslides with ellipsoidal or truncated failure surfaces. We test the model in the La Arenosa catchment, northern Colombian Andes. The results are compared to those yielded with the corresponding deterministic analyses and with other physically based models applied in the same catchment. Finally, the model results are evaluated against a landslide inventory using a confusion matrix and Receiver Operating Characteristic (ROC) analysis. The model performs reasonably well, the infinite slope stability model showing a better performance. The outcomes are, however, rather conservative, pointing to possible challenges with regard to the geotechnical and geo-hydraulic parameterization. The results also highlight the importance to perform probabilistic instead of – or in addition to – deterministic slope stability analyses.

scholarly journals Dealing with deep uncertainties in landslide modelling for disaster risk reduction under climate change

2017 ◽  
Vol 17 (2) ◽  
pp. 225-241 ◽  
Author(s):  
Susana Almeida ◽  
Elizabeth Ann Holcombe ◽  
Francesca Pianosi ◽  
Thorsten Wagener
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Numerical Models ◽  
Landslide Risk ◽  
Residual Soils ◽  
Loss Of Life ◽  
Economic Changes ◽  
Critical Thresholds ◽  
Stability Model ◽  
Steep Slopes

Abstract. Landslides have large negative economic and societal impacts, including loss of life and damage to infrastructure. Slope stability assessment is a vital tool for landslide risk management, but high levels of uncertainty often challenge its usefulness. Uncertainties are associated with the numerical model used to assess slope stability and its parameters, with the data characterizing the geometric, geotechnic and hydrologic properties of the slope, and with hazard triggers (e.g. rainfall). Uncertainties associated with many of these factors are also likely to be exacerbated further by future climatic and socio-economic changes, such as increased urbanization and resultant land use change. In this study, we illustrate how numerical models can be used to explore the uncertain factors that influence potential future landslide hazard using a bottom-up strategy. Specifically, we link the Combined Hydrology And Stability Model (CHASM) with sensitivity analysis and Classification And Regression Trees (CART) to identify critical thresholds in slope properties and climatic (rainfall) drivers that lead to slope failure. We apply our approach to a slope in the Caribbean, an area that is naturally susceptible to landslides due to a combination of high rainfall rates, steep slopes, and highly weathered residual soils. For this particular slope, we find that uncertainties regarding some slope properties (namely thickness and effective cohesion of topsoil) are as important as the uncertainties related to future rainfall conditions. Furthermore, we show that 89 % of the expected behaviour of the studied slope can be characterized based on only two variables – the ratio of topsoil thickness to cohesion and the ratio of rainfall intensity to duration.

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