Stability of sandy slopes under seepage conditions

Ghiassian, H.; Ghareh, Soheil

doi:10.1007/s10346-008-0132-5

Cited by 60 publications

(22 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All forces are calculated as unit forces where the width corresponds to 1 unit length (e.g., Mergili et al 2014;Fellin 2014;Ghiassian and Ghareh 2008). The model's formulae and the workflow for parameter testing were implemented in the R open source software environment for statistical computing (R Core Team 2016).…”

Section: Methodsmentioning

confidence: 99%

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

2017

View full text Add to dashboard Cite

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.

show abstract

Section: Methodsmentioning

confidence: 99%

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

2017

View full text Add to dashboard Cite

show abstract

“…Comprehensive research on seepage erosion and piping mechanisms in landslide dams (Meyer et al 1994;Davies and McSaveney 2011;Wang et al 2013;Okeke and Wang 2016;Wang et al in press), levees and earth embankments (Richards and Reddy 2007), hillslopes (Ghiassian and Ghareh 2008), and stream banks (Fox and Wilson 2010), have all been completed. Variations in experimental results and opinions are strictly based on the design and method of experiment adopted, coupled with size and scale effects arising from the nature of material tested.…”

Section: Brief Review Of Seepage Erosion In Soilsmentioning

confidence: 99%

Critical hydraulic gradients for seepage-induced failure of landslide dams

Okeke

Wang

2016

Geoenviron Disasters

View full text Add to dashboard Cite

Background: Landslide dams formed by rock avalanche processes usually fail by seepage erosion. This has been related to the complex sedimentological characteristics of rock avalanche dams which are mostly dominated by fragmented and pulverized materials. This paper presents a comprehensive experimental programme which evaluates the critical hydraulic and geometrical conditions for seepage-induced failure of landslide dams. The experiments were conducted in a flume tank specifically designed to monitor time-dependent transient changes in pore-water pressures within the unsaturated dam materials under steady-state seepage. Dam models of different geometries were built with either mixed or homogeneous materials. Two critical hydraulic gradients corresponding to the onset of seepage erosion initiation and collapse of the dam crest were determined for different upstream inflow rates, antecedent moisture contents, compactive efforts, grain size ranges, and dam geometries.

show abstract

“…The slope fails at or near the contact between the soil colluvium and impervious bedrock. The shear strength acting along the slip surface is quantified by applying the Mohr-Coulomb criterion, and F s of the infinite slope can be readily expressed as (Christian and Urzua 1998;Ghiassian and Ghareh 2008;Griffiths et al 2008) the ratio of the available resisting force R to the driving force S…”

Section: Calculation Examplesmentioning

confidence: 99%

“…The cohesion c and friction angle φ are soil shear strength parameters. The magnitude of the seepage force F w is associated with the hydraulic gradient and the soil volume, which arises due to the water flow parallel to the slope in the saturated layer (Ghiassian and Ghareh 2008). Furthermore, the infinite slope model is applied to a case representative of a common stability problem with the loose soil deposits in the southwest of China (Tang and Zhang 2011).…”

Section: Calculation Examplesmentioning

confidence: 99%

Development of fragility functions for slope instability analysis

2014

Landslides

View full text Add to dashboard Cite

This paper presents a methodology for constructing fragility functions to characterise slope stability under a range of catastrophic earthquakes and rainfalls. The procedures for creating fragility functions, including the first-order reliability method (FORM) and the copula-based sampling method (CBSM), are demonstrated using a selection of typical slopes. The most common failure modes are included, such as the shallow sliding of an infinite slope, circular slip surface of a homogeneous slope, and tetrahedral wedge failure in a rock slope. Owing to the proposed approach, the fragility function can be applied to quantify the failure probabilities over a range of loading conditions with ease, as these are attributed to a function, rather than a design point. The advantage of these definitions is that the uncertainties of correlated soil shear strengths can be incorporated into the reliability models. The established procedure can provide a basis for describing vulnerable behaviour of a slope under various loading conditions and geometries.

show abstract

Stability of sandy slopes under seepage conditions

Cited by 60 publications

References 19 publications

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

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

Critical hydraulic gradients for seepage-induced failure of landslide dams

Development of fragility functions for slope instability analysis

Contact Info

Product

Resources

About