The Experts below are selected from a list of 48813 Experts worldwide ranked by ideXlab platform
D V Griffiths - One of the best experts on this subject based on the ideXlab platform.
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probabilistic seismic Slope Stability analysis and design
Canadian Geotechnical Journal, 2019Co-Authors: Jesse Burgess, D V Griffiths, Gordon A FentonAbstract:Deterministic seismic Slope Stability design charts for cohesive–frictional ( ) soils are traditionally used by geotechnical engineers to include the effects of earthquakes on Slopes. These charts ...
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three dimensional Slope Stability analysis by elasto plastic finite elements
Geotechnique, 2007Co-Authors: D V Griffiths, R M MarquezAbstract:Slope Stability analysis is one of the oldest applications in geotechnical engineering, yet it remains one of the most active areas of study in both research and practice. The vast majority of Slope Stability analyses are performed in two dimensions under the assumption of plane strain conditions. Even when two-dimensional (2D) conditions are not appropriate, three-dimensional (3D) analysis is rarely performed. There are a number of reasons for this. The majority of work on this subject strongly suggests that the 2D factor of safety is conservative (i.e. lower than the ‘true’ 3D factor of safety). Even when 3D may be justified on geometric grounds, the available methods, being often based on extrapolations of 2D ‘methods of slices’ to 3D ‘methods of columns’, are complex, involve numerous assumptions, and are not readily modified to account for realistic boundary conditions in the third dimension such as sloping abutments. The power and versatility of the elasto-plastic finite element approach to Slope st...
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probabilistic Slope Stability analysis by finite elements
Journal of Geotechnical and Geoenvironmental Engineering, 2004Co-Authors: D V Griffiths, Gordon A FentonAbstract:In this paper we investigate the probability of failure of a cohesive Slope using both simple and more advanced probabilistic analysis tools. The influence of local averaging on the probability of failure of a test problem is thoroughly investigated. In the simple approach, classical Slope Stability analysis techniques are used, and the shear strength is treated as a single random variable. The advanced method, called the random finite-element method (RFEM), uses elastoplasticity combined with random field theory. The RFEM method is shown to offer many advantages over traditional probabilistic Slope Stability techniques, because it enables Slope failure to develop naturally by “seeking out” the most critical mechanism. Of particular importance in this work is the conclusion that simplified probabilistic analysis, in which spatial variability is ignored by assuming perfect correlation, can lead to unconservative estimates of the probability of failure. This contradicts the findings of other investigators w...
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Slope Stability analysis by finite elements
Geotechnique, 1999Co-Authors: D V Griffiths, P A LaneAbstract:The majority of Slope Stability analyses performed in practice still use traditional limit equilibrium approaches involving methods of slices that have remained essentially unchanged for decades. This was not the outcome envisaged when Whitman & Bailey (1967) set criteria for the then emerging methods to become readily accessible to all engineers. The finite element method represents a powerful alternative approach for Slope Stability analysis which is accurate, versatile and requires fewer a priori assumptions, especially, regarding the failure mechanism. Slope failure in the finite element model occurs 'naturally' through the zones in which the shear strength of the soil is insufficient to resist the shear stresses. The paper describes several examples of finite element Slope Stability analysis with comparison against other solution methods, including the influence of a free surface on Slope and dam Stability. Graphical output is included to illustrate deformations and mechanisms of failure. It is argue...
U Ten S Brink - One of the best experts on this subject based on the ideXlab platform.
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seismicity and sedimentation rate effects on submarine Slope Stability
Geology, 2016Co-Authors: U Ten S Brink, Brian D Andrews, N C MillerAbstract:We explore the effects of earthquake frequency and sedimentation rate on submarine Slope Stability by extracting correlations between morphological and geological parameters in 10 continental margins. Slope Stability increases with increasing frequency of earthquakes and decreasing sedimentation rate. This increase in Stability is nonlinear (power law with b < 0.5), accelerating with decreasing interseismic sediment accumulation. The correlation is interpreted as evidence for sediment densification and associated shear strength gain induced by repeated seismic shaking. Outliers to this correlation likely identify margins where tectonic activity leads to relatively rapid oversteepening of the Slope.
Leonardo Noto - One of the best experts on this subject based on the ideXlab platform.
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the use of soil water retention curve models in analyzing Slope Stability in differently structured soils
Catena, 2017Co-Authors: Chiara Antinoro, Elisa Arnone, Leonardo NotoAbstract:Abstract This study analyzes whether and at what rate the parameterization of the Soil Water Retention Curve (SWRC) affects the analysis of shallow Slope Stability for differently structured unsaturated soils. Advanced empirical or physically-based equations of SWRCs have been proposed in literature to describe soil systems characterized by the so-called bimodal porous domain. In unsaturated soils, SWRC affects the Stability assessment in two ways. It influences the resistance properties in terms of shear strengths, which depend on the soil water suction; and it affects the hydrological process modeling (e.g. infiltration) directly influencing soil moisture patterns and indirectly influencing Slope Stability. Most of the formulations proposed to predict the shear strength of unsaturated soils require the definition of an χ parameter that tunes the contribution of the suction effect to a rate proportional to the saturation conditions. In this study, a set of experiments was carried out in order to analyze both the mechanical and hydrological effects of SWRC on Slope Stability. First, three SWRC models were calibrated on different soil textures. Then, Slope Stability analyses were carried out on a synthetic hillSlope supposed to be characterized alternatively and homogenously by the different soils. The factor of safety (FS) of the Slope was computed first, at given states of hydrological conditions (i.e., fixed soil moisture), and then at dynamic hydrological conditions simulated by solving the 1D Richards's equation. Two different formulations of the χ parameter were also used. Finally, a sensitivity analysis of the SWRC models and the χ formulations for Slope Stability were evaluated for different Slope angles and mechanical properties. The results indicated that for clayey (and bimodal) soils, changes in FS obtained with different SWRC models can be significant, especially at soil moisture values close to the residual zone. In sandy (and unimodal) soils, the choice of χ formulations can be more important. The variation of FS decreases as the Slope angle increases or the friction angle decreases.
Alexia Stokes - One of the best experts on this subject based on the ideXlab platform.
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the influence of plant diversity on Slope Stability in a moist evergreen deciduous forest
Ecological Engineering, 2010Co-Authors: Marie Genet, Alexia Stokes, Thierry Fourcaud, J E NorrisAbstract:The influence of plant diversity on Slope Stability was investigated at early phases of succession in a mixed forest in Sichuan, China. The first phase comprised big node bamboo (Phyllostachys nidularia Munro) only. In the second phase, bamboo co-existed with deciduous tree species and in the third phase, deciduous species existed alone. Root density at different depths and root tensile strength were determined for each species. The factor of safety (FOS) was calculated for Slopes with and without vegetation for each succession phase. For phase 2, FOS was determined for different species mixtures and positions. In phase 3, simulations were performed with a single tree at the top, middle or toe of the Slope. Due to its shallow root system, bamboo contributed little to Slope Stability. In simulations with the tree at the top or middle of the Slope, FOS decreased because tree weight added a surcharge to the Slope. FOS increased with the tree at the bottom of the Slope. Different mixtures of species along the Slope had no influence on FOS. Differences in root tensile strength between species played a small role in FOS calculations, and tree size and density were the most important factors affecting Slope Stability, excluding hydrological factors.
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using three dimensional plant root architecture in models of shallow Slope Stability
Annals of Botany, 2007Co-Authors: Frederic Danjon, David H Barker, Michael Drexhage, Alexia StokesAbstract:Background: The contribution of vegetation to shallow-Slope Stability is of major importance in landslide-prone regions. However, existing Slope Stability models use only limited plant root architectural parameters. This study aims to provide a chain of tools useful for determining the contribution of tree roots to soil reinforcement. Methods: Three-dimensional digitizing in situ was used to obtain accurate root system architecture data for mature Quercus alba in two forest stands. These data were used as input to tools developed, which analyse the spatial position of roots, topology and geometry. The contribution of roots to soil reinforcement was determined by calculating additional soil cohesion using the limit equilibrium model, and the factor of safety (FOS) using an existing Slope Stability model, Slip4Ex. Key Results: Existing models may incorrectly estimate the additional soil cohesion provided by roots, as the spatial position of roots crossing the potential slip surface is usually not taken into account. However, most soil reinforcement by roots occurs close to the tree stem and is negligible at a distance >1·0 m from the tree, and therefore global values of FOS for a Slope do not take into account local slippage along the Slope. Conclusions: Within a forest stand on a landslide-prone Slope, soil fixation by roots can be minimal between uniform rows of trees, leading to local soil slippage. Therefore, staggered rows of trees would improve overall Slope Stability, as trees would arrest the downward movement of soil. The chain of tools consisting of both software (free for non-commercial use) and functions available from the first author will enable a more accurate description and use of root architectural parameters in standard Slope Stability analyses.
Jinqi Zhu - One of the best experts on this subject based on the ideXlab platform.
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influence of the spatial layout of plant roots on Slope Stability
Ecological Engineering, 2016Co-Authors: Yunqi Wang, Huilan Zhang, Yujie Wang, Shuangshuang Song, Jinqi ZhuAbstract:Abstract Background and aims Technology involving the use of plants on Slopes to prevent shallow landslides and Slope inStability has been extensively used worldwide. A reasonable collocation of plant and engineering measures can prevent water loss and soil erosion effectively. Because of the complicated distribution of roots in soil, there must be a simpler and more workable method of studying the role of plant roots on Slope Stability. The purpose of this paper is to investigate the affects of shallow-rooted plants on Slope Stability and provide reliable theoretical support in the process of ecological environmental constructions. Methods Here we used numerical simulations to examine the influence of plant roots on soil shear strength as the increase of soil cohesion. Then, we generalized root architecture to be soil bodies consisting of different cohesive strengths. Changes of stress and pressure were simulated within the range of soil within plant roots on the Slope. The intensity attenuation method was here used to calculate the safety factor of Slope. Results Tapered roots were found to be associated with more serious soil loss due to the maximal velocity of 14 m/s within the scope of plant main stems. Widely root distribution in H-type showed a cyclical effect on the Slope on condition that flow shear stress was small. Conclusions Young trees have little impact on Slope Stability which is 3.76–7.85% merely comparing to the bare Slopes regardless of rainfall. When root distributions are similar in topsoil, the resistances to the radial stress are not obvious. Widely distributed (H-type) and tapered root (VH-type) architecture are recommended in biological engineering projects.
