Effects of Soil-Vegetation-Atmosphere Interaction on the Stability of a Clay Slope: A Case Study

Pedone, Giuseppe; Tsiampousi, Aikaterini; Cotecchia, Federica; Zdravković, Lidija

doi:10.1051/e3sconf/20160915002

Cited by 7 publications

(3 citation statements)

References 16 publications

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“…Mechanical soil properties, such as stiffness and strength, have traditionally monopolised the interest of practicing geotechnical engineers and researchers. The effect of pore water pressures (pwp) and of their variation on the stability and serviceability of geotechnical structures [1][2][3] and natural slopes [4,5], and on the coefficient of earth pressure at rest [6], has also long been recognised. Although, by association, the influence of hydraulic parameters, such as permeability and soil-water retention, is widely accepted in theory [7,8], in practice it is rare that complete and comprehensive laboratory and field data are dedicated to determining hydraulic parameters with accuracy and confidence, perhaps owing to the difficulty of the task.…”

Section: Introductionmentioning

confidence: 99%

The importance of permeability in modelling soil-atmosphere interaction

Tsiampousi

2023

E3S Web of Conf.

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Soil-atmosphere interaction has been attracting increasing interest as the seasonal variation of pore water pressures (pwp) has been linked to a variety of geotechnical problems (e.g. slope stability and serviceability, foundation subsidence or swelling, desiccation cracking etc.) or has been identified as part of the solution of geotechnical problems (e.g. in sustainable urban drainage systems). Prediction of how the pwp will change within soils of low permeability under the combined effect of evapotranspiration and precipitation requires adequate knowledge of the soil permeability and how it varies spatially (e.g with depth) and temporally (e.g. with suction or degree of saturation, void ratio or due to the opening and closing of desiccation cracks). Nonetheless, in-situ measurements of permeability that satisfy both the spatial and temporal variation are difficult. In order to clarify the importance of variable permeability in predicting pwp variations under atmospheric loads, a series of one- and two-dimensional finite element analyses was performed, where the permeability model and the variation of permeability were parametrically studied. The results demonstrated that the variation of permeability, as well as the model employed in the analysis, e.g. allowing or not for desiccation cracking, influenced the values of suction calculated as well as the pwp profile with depth, highlighting the importance of estimating the spatial and temporal variation of permeability with some level of confidence.

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Section: Introductionmentioning

confidence: 99%

The importance of permeability in modelling soil-atmosphere interaction

Tsiampousi

2023

E3S Web of Conf.

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“…Engineered infrastructure slopes [1][2][3], i.e, slopes formed by excavating or compacting soil to accommodate highways, railways etc., and natural slopes [4,5] have long been known to be affected by interaction with the atmosphere due to the seasonal variation of pore water pressure [6], which affects the stresses, stiffness and the coefficient of earth pressure at rest [7]. For example, [2] observed that modestly vegetated slopes are prone to deep seated failures, primarily after wet periods, whereas densely vegetated slope suffer from severe serviceability problems, which are likely to occur towards the end of dry periods.…”

Section: Introductionmentioning

confidence: 99%

3D effects of soil-atmosphere interaction on infrastructure slope stability

Tsiampousi

2023

E3S Web of Conf.

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It has long been established that pore water pressure (pwp) variations affect the stability and serviceability of slopes. Pwp variations may be due to consolidation/swelling processes within soils of low permeability or may be due to seasonal evapotranspiration and precipitation processes. The simultaneous study of such phenomena and of hydro-mechanical coupling in sloping ground requires use of advancednumerical methods. Often, infrastructure slopes are considered in plane strain (two-dimensional) conditions for simplicity and to date this is the case for most numerical analyses considering soil-atmosphere interaction. However, this approach makes it impossible to study the longitudinal extent of a possible slip surface forming following vegetation removal. Three-dimensional, fully-coupled numerical analyses of acut slope were performed herein to study the effect of vegetation clearance on stability and explore numerically ways of implementing effective vegetation management.

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“…During and after excavation, the stress redistribution due to dewatering, unloading and swelling can initiate new cracks and fissures, or open the existing ones. Such discontinuities act as seepage paths which increase the permeability of the soil mass and subsequently affect the rate of NEPWP generation and dissipation (Vaughan and Walbancke, 2009, Eigenbrod, 1975, James, 1970a, Pedone et al, 2016, Vaughan and Walbancke, 1973, Griffiths and Li, 1993. Also, the dewatering and desaturating of soil may result in drying cracking (Hueckel et al, 2013, Peron et al, 2009.…”

Section: Introductionmentioning

confidence: 99%

Effect of negative excess pore-water pressure on the stability of excavated slopes

Ghadrdan

Shaghaghi

Tolooiyan

2020

Géotechnique Letters

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The generation of Negative Excess Pore-Water Pressure (NEPWP) due to the excavation of saturated soils under undrained conditions and the following dissipation of this phenomenon over time may result in different shortand long-term slope instability. The NEPWP generated due to excavation gradually decreases towards equilibrium or in some cases steady seepage. Hence, total pore-water pressures immediately after the excavation are lower than the ultimate equilibrium values, leading to the reduction of the average effective stresses in the slope and subsequently threatening the stability in the long term. In this research, the stability of three benchmark civil and mining excavations has been studied, considering the effects of generation and dissipation of NEPWP. A series of numerical simulations are conducted to determine the role of in-situ stresses and time in NEPWP dissipation as well as the consequent effects on the stability of the excavated slopes. To conduct a realistic time-dependent transient analysis, a fully-coupled hydro-geomechanical formulation has been employed. Results show that in general, higher removal of stress levels leads to higher NEPWP generation and higher factor of safety values in the short term. Thereafter, the dissipation of NEPWP threatens the long-term stability of the excavation.

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Effects of Soil-Vegetation-Atmosphere Interaction on the Stability of a Clay Slope: A Case Study

Cited by 7 publications

References 16 publications

The importance of permeability in modelling soil-atmosphere interaction

The importance of permeability in modelling soil-atmosphere interaction

3D effects of soil-atmosphere interaction on infrastructure slope stability

Effect of negative excess pore-water pressure on the stability of excavated slopes

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