Principle of Effective Stress in Variably Saturated Porous Media

Lu, Ning; Khalili, Nasser; Nikooee, Ehsan; Hassanizadeh, S. Majid

doi:10.2136/vzj2014.04.0038

Cited by 13 publications

(5 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In geotechnical terms, the collapsing behavior of the granular soils around the den system can be described by using the principle of effective stress for unsaturated soils [e.g., Fredlund and Rahardjo, 1993;Lu and Likos, 2004;Lu et al, 2014]. Bishop's [1959] effective stress for unsaturated soils can be expressed as r 0 5ðr2u a Þ1vðu a 2u w Þ, where r is the total stress, u a is the pore air pressure, ðr2u a Þ is the net normal stress, v is the effective stress parameter, u w is the pore water pressure, ðu a 2u w Þ is the matric suction, and v ðu a 2u w Þ is the suction stress.…”

Section: A5 Wall Stability Analysismentioning

confidence: 99%

Evidence of an emerging levee failure mechanism causing disastrous floods in Italy

Orlandini

Moretti

Albertson

2015

Water Resources Research

View full text Add to dashboard Cite

A levee failure occurred along the Secchia River, Northern Italy, on 19 January 2014, resulting in flood damage in excess of $500 million. In response to this failure, immediate surveillance of other levees in the region led to the identification of a second breach developing on the neighboring Panaro River, where rapid mitigation efforts were successful in averting a full levee failure. The paired breach events that occurred along the Secchia and Panaro Rivers provided an excellent window on an emerging levee failure mechanism. In the Secchia River, by combining the information content of photographs taken from helicopters in the early stage of breach development and 10 cm resolution aerial photographs taken in 2010 and 2012, animal burrows were found to exist in the precise levee location where the breach originated. In the Panaro River, internal erosion was observed to occur at a location where a crested porcupine den was known to exist and this erosion led to the collapse of the levee top. This paper uses detailed numerical modeling of rainfall, river flow, and variably saturated flow in the levee to explore the hydraulic and geotechnical mechanisms that were triggered along the Secchia and Panaro Rivers by activities of burrowing animals leading to levee failures. As habitats become more fragmented and constrained along river corridors, it is possible that this failure mechanism could become more prevalent and, therefore, will demand greater attention in both the design and maintenance of earthen hydraulic structures as well as in wildlife management.

show abstract

Section: A5 Wall Stability Analysismentioning

confidence: 99%

Evidence of an emerging levee failure mechanism causing disastrous floods in Italy

Orlandini

Moretti

Albertson

2015

Water Resources Research

View full text Add to dashboard Cite

show abstract

“…The dependencies of χ and σ' on these factors have been studied by many authors e.g. Bolzon et al (1996), Khalili and Khabbaz (1998) Lu et al (2014). In these studies slightly different terminologies have been adopted for χ and σ'.…”

Section: Problem Set-upmentioning

confidence: 99%

Incorporating suction in to stability charts for unsaturated soil slopes

Russell

2019

JGS Special Publication

View full text Add to dashboard Cite

This paper presents charts derived from stability analyses of curvilinear slopes in non-homogeneous unsaturated soils. The charts enable quick and inexpensive stability analyses to be conducted in practice. The soils are assumed to obey the Mohr-Coulomb failure criterion. Suction effects are captured using the effective stress concept. Cohesion and the contribution of suction to the effective stress are linear functions of depth. It is shown that a stable curvilinear slope profile is uniquely governed by dimensionless parameters. The charts are presented using these dimensionless parameters and may be used in the preliminary design of stable curvilinear slopes. In general, suction has a similar influence to cohesion, and as the contribution of suction to effective stress increases, steeper curvilinear slopes become stable. An example of application is included showing the design of a curvilinear slope.

show abstract

“…Considering the inconsistencies between traditional methods of two‐phase flow in porous media and recent observations and theories, a question arises regarding the extent to which these differences affect the mechanical behavior of the porous medium. The contribution of the presence of multiple fluids in a porous medium to the mechanical behavior is captured through the concept of effective stress (Fazli Ghiyasabadi et al., 2021; Huyghe et al., 2017; Khalili et al., 2004; Lu et al., 2014; Nikooee et al., 2012; Nikooee, Habibagahi, et al., 2013). Bishop (1959) has formulated the effective stress for a system of two immiscible fluids (such as air and water in an unsaturated soil) as presented in Equation ().…”

Section: Introductionmentioning

confidence: 99%

Effects of dynamic capillarity on the shear strength of sandy soils during transient two‐phase flow: Insights from non‐equilibrium triaxial simulations

Daman Shokouh,

Nikooee,

Habibagahi

et al. 2024

Vadose Zone Journal

Self Cite

View full text Add to dashboard Cite

Modeling two‐phase flow in unsaturated porous media is not only important to vadose zone hydrology but also of great value in diverse disciplines. Common approaches use a simplified relationship between fluid pressure difference and saturation, neglecting the influence of saturation change rates. However, many studies have suggested that the applicability of this approach is limited to situations where the rate of change in saturation is insignificant. Despite several studies highlighting the importance of non‐equilibrium capillarity effects in unsaturated flow modeling, its significance in the mechanical response of the porous medium remains unclear. This study thus aims to address this gap by comparing the simulation results of the traditional static approach and an advanced approach that incorporates dynamic capillarity effects. The comparison is conducted under various flow boundary conditions to assess the magnitude of the differences between the two approaches. The results indicate that as the hydraulic boundary conditions’ absolute values increase, the contrast between the mechanical response of the two simulation scenarios (dynamic and static) becomes more significant. For instance, the dynamic model can predict shear strengths up to 50% higher than the static model. This highlights the importance of considering non‐equilibrium effects while modeling the mechanical behavior of an unsaturated porous medium. Finally, the parametric study of the effect of dynamic coefficient, air entry value, and saturated conductivity reveals the more pronounced effect of the dynamic coefficient on the mechanical response.

show abstract

Principle of Effective Stress in Variably Saturated Porous Media

Cited by 13 publications

References 27 publications

Evidence of an emerging levee failure mechanism causing disastrous floods in Italy

Evidence of an emerging levee failure mechanism causing disastrous floods in Italy

Incorporating suction in to stability charts for unsaturated soil slopes

Effects of dynamic capillarity on the shear strength of sandy soils during transient two‐phase flow: Insights from non‐equilibrium triaxial simulations

Contact Info

Product

Resources

About