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 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.

Infinite Slope Stability under Transient Rainfall Infiltration Conditions

2014 ◽  
Vol 501-504 ◽  
pp. 395-398 ◽  
Author(s):  
Yu Fei Kong ◽  
Jian Liu ◽  
Hong Gang Shi ◽  
Long Ying Zhang ◽  
Heng Zhao ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Safety Factor ◽  
Underground Water ◽  
Rainfall Infiltration ◽  
Infiltration Process ◽  
Infinite Slope ◽  
Seepage Analysis ◽  
Infiltration Model ◽  
Two Stages

The infiltration process of infinite slopes was studied with modified Green-Ampt infiltration model. The process was divided into two stages, in which the depth of the wetting zone and underground water was calculated. Stability analysis considering different sliding patterns was conducted on the basis of seepage analysis. The safety factor of infinite slopes at different time stages has been derived. Equations in this paper could be used for predicting rain-induced landslides with limited parameters available.

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

Comparison of the performance of spatial landslide prediction with TRIGRS1D and SCOOPS3D models and parameter optimization: application to the Oltrepò Pavese

2020 ◽  
Author(s):  
Nunziarita Palazzolo ◽  
David J. Peres ◽  
Massimiliano Bordoni ◽  
Claudia Meisina ◽  
Enrico Creaco ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Three Dimensional ◽  
Slope Stability Analysis ◽  
Hazard Mapping ◽  
Catchment Scale ◽  
Infinite Slope ◽  
Infinite Slope Stability Model ◽  
Stability Model ◽  
Positive Rate

<p>Physically based models based on the combination of hydrological and slope stability models are important tools in spatial and temporal prediction of landslides, since they can be used for hazard mapping as an aid for land planning. In many applications, hydrological models are combined with very simple infinite slope stability analysis, given that multi-dimensional analysis is more computationally demanding. Only a few studies have attempted to apply such algorithms to the catchment scale. Thus, there is a need for more studies on this issue, also to understand the real advantages of applying multi-dimensional slope stability analysis in comparison with the one-dimensional. </p><p>This study aims to compare the performance of two different forecasting models, namely the infinite slope and the three-dimensional stability analysis by SCOOPS3D (Software to analyze three-dimensional slope stability throughout a digital landscape), a very efficient model proposed by USGS to be applied to the catchment scale, which has seldom been applied so far in the literature. In particular, TRIGRS (Transient Rainfall Infiltration and Grid-Based Regional Slope-stability Model) is used for hydrological analysis.  Then the resulting pressure head field is used first as input to the infinite slope stability model embedded into TRIGRS program itself and then as input to SCOOPS3D. To calibrate the terrain stability-related parameters of either piece of software, a multi-objective optimization is proposed in this work to maximize the model predictability performance, in an attempt to optimize ROC performance statistics, i.e. to maximize the true positive rate while simultaneously minimizing the false positive rate.</p><p>The approach was applied to a real case study, a catchment in the Oltrepò Pavese (northern Italy), in which the areas of triggered landslides were accurately monitored during an extreme rainfall on 27-28 April, 2009, featuring 160 mm in 48 h. Compared to other works in the scientific literature, in which only a generic point of location of landslides was known, the present work benefits from the availability of a detailed landslide inventory containing observed landslide shapes.</p><p>The results point out the significantly better performance of  SCOOPS3D, in comparison with the infinite slope stability. Though SCOOPS3D seems to overestimate landslide prone areas, the 3D method is more realistic than the 1D method as far as the slip surface definition is concerned. Therefore, the proposed methodology, lying in the use of SCOOPS 3D with optimized parameters, can be a helpful tool for providing multiple landslide hazard maps for planning.</p>

Slope Stability Analyses of Zoned Dam Under Steady State Condition/Case Study

2021 ◽  
Author(s):  
Ako Daraei ◽  
◽  
Dlshad Ahmed ◽  
Keyword(s):  
Steady State ◽  
Slope Stability ◽  
Safety Factor ◽  
Equilibrium Condition ◽  
Factor Of Safety ◽  
Slope Instability ◽  
Static Equilibrium ◽  
State Condition ◽  
Army Corps ◽  
Steady State Condition

Earth and rock are the principal materials from which dams are constructed, these kinds of dams are called embankment dams. The conventional limit equilibrium method has dominated use over any other method for analyzing slope stability. In this paper, Spence, Morgenstern-price, the Ordinary method of slices, and Janbu simplified methods are used in order to find out how near, far Aquban dam from the verge failure which is located in Erbil-Kurdistan/Iraq. In present study, the focus is mainly drawn on analyses of steady-state condition. To compute the factor of safety, the study utilized SLOPE/W software. The results show that there is no major difference in a safety factor and a critical slip surface position between all the methods which are used in the study. In addition, all used methods offered a more than the minimum required safety factory which is given by the U.S. Army Corps of Engineers so this ensures that the dam against slope instability is on the safe side. According to the results obtained from this study, Janbu simplified method which considers only force equilibrium condition produced the lowest factor of safety, while the highest and almost identical factor of safety generated from the methods that satisfy all the static equilibrium condition (Spencer and Morgenstern-Price methods) give. Therefore, a reasonably reliable and higher value of safety factor is given by the methods which satisfy all static equilibrium conditions.

scholarly journals THE SAFETY FACTOR ANALYSIS OF THE MARINE SLOPE STABILITY MODEL ON THE ACCESS CHANNEL OF MARINE CENTRE PLAN CIREBON, WEST JAVA.

2016 ◽  
Vol 25 (2) ◽  
pp. 89
Author(s):  
Franto Novico ◽  
Nur Adi Kristanto
Keyword(s):  
Slope Stability ◽  
Safety Factor ◽  
Laboratory Tests ◽  
Channel Model ◽  
Safety Factors ◽  
High Deformation ◽  
Data Analyses ◽  
Access Channel ◽  
Stability Model ◽  
Slope Channel

This study is focused on access channel model that safety factors of some slopes stability would be investigated. Plaxis version 8 is applied to analyze a magnitude of safety factors and displacements based on three different slopes of access channel there are 30°, 45° and 60°. Furthermore, parameters are adopted from geotechnical drilling and laboratory tests. A finite element is applied as a simple model to analyze within a Mohr-coulomb equation. Based on soil data analyses on Marine Center Plan, indicates low safety factor and high deformation. As results, 10 to 40 meters deformation of the slopes and 0.80 to 2.34 of safety factor are obtained of the models. For that reason, a combination between slope channel and infrastructure must be considered. Keywords: Safety factor, slope stability, access channel, Marine centre, Plaxis Kajian ini dilakukan terhadap faktor keamanan dari beberapa jenis kemiringan dinding alur pelayaran yang selanjutnya dilakukan pemodelan dengan menggunakan alur pelayaran Besarnya keruntuhan dan faktor keamanan pada beberapa sudut kemiringan yang berbeda telah dianalisis dengan menggunakan perangkat lunak geoteknik Plaxis Versi 8. Tiga jenis kemiringan yang berbeda telah dibuat yaitu sudut kemiringan 30°, 45° dan 60°. Sebagai data masukan, parameter diambil berdasarkan hasil pemboran geoteknik yang telah dianalisis di laboratorium. Model sederhana elemen terbatas telah dibuat dan dianalisis berdasarkan persamaan Mohr-Coulumb. Berdasarkan analisis data tanah pada rencana Marine Centre menunjukan faktor keamanan yang rendah dan deformasi yang besar. Total deformasi yang dihasilkan berkisar 10-40 meter dengan nilai faktor keamanan 0,80~2,34. Oleh karena itu, dari hasil tersebut perlu dipertimbangkan untuk mengkombinasikan kemiringan alur dengan infrastruktur. Kata kunci : faktor keamanan, kemiringan lereng, alur pelayaran, Marine centre, Plaxis

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

2015 ◽  
Vol 15 (8) ◽  
pp. 1835-1849 ◽  
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, 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 a ROC (receiver operating characteristics) graph. In addition, the results of the proposed approach were compared with the previous approach used: a 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.

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