Hydraulic hysteresis effects on the coupled flow–deformation processes in unsaturated soils: Numerical formulation and slope stability analysis

Hu, Ran; Hong, Jia-Min; Chen, Yi‐Feng; Zhou, Chuangbing

doi:10.1016/j.apm.2017.09.023

Cited by 17 publications

(11 citation statements)

References 67 publications

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“…While many recent studies have considered some hydro-mechanical processes in slopes (e.g. Borja and White 2010;Choo et al 2016;Davies et al 2014;Hu et al 2011Hu et al , 2018Liu et al 2017;Qi and Vanapalli 2015;Wu et al 2016;Yang et al 2017), they are more suited to natural slopes subjected to rainfall. For spoil dumps, the long-term stability is vital to the feasibility of land rehabilitation and reclamation plans.…”

Section: Methods Of Slope Stability Analysismentioning

confidence: 99%

Stability and characterisation of spoil heaps in European surface lignite mines: a state-of-the-art review in light of new data

et al. 2019

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The large amount of spoil material produced during the mining process imposes a significant economic and environmental liability on lignite producers. In this context, the present paper provides an overview of the geotechnical characteristics of European lignite mine spoil heaps and discusses their significance to the stability of the heaps. In order to achieve this, samples collected from spoil heaps of Polish, Czech and Greek mines are analysed and the results are compiled with data from the literature. A major conclusion drawn is that both physical and engineering properties of spoil heaps indicate a noteworthy variability, which is larger than typical in situ ground material. This is because of the additional factors affecting spoil heap deposition, such as the transportation and dumping method. Furthermore, failure mechanisms and case histories of large instabilities in lignite spoil heaps are critically discussed in order to better understand triggering failure mechanisms. It is concluded that classical assumptions made for natural soil slopes and relevant limit equilibrium models should be cautiously applied to spoil heaps. The challenges associated with numerical and probabilistic modelling of spoil heap stability, such as the inherent spatial variability of spoils and the time-dependent changes in their geotechnical properties, are also critically discussed. Finally, important research gaps in design and analysis of spoil heap stability, such as the absence of appropriate constitutive models developed specifically for spoil materials, are summarised.

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Section: Methods Of Slope Stability Analysismentioning

confidence: 99%

Stability and characterisation of spoil heaps in European surface lignite mines: a state-of-the-art review in light of new data

et al. 2019

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“…The degree of saturation can be approximately substituted for the matric suction coefficient [11,19,[50][51][52]. Equation (12) was derived from Equation (11) by substituting the degree of saturation for χ.…”

Section: Rainfall Infiltration Analysismentioning

confidence: 99%

“…Although numerous empirically based approaches have been widely applied to large areas using simple methods, deterministic physics-based approaches are preferable for a better understanding of the mechanisms of shallow landslides [13]. Numerous physically based studies have investigated infiltration behavior during rainfall using various approaches: (1) Adopting assumptions for simplification to solve the differential equation of Richards [14] by applying a single-phase fluid (water) flow [3,10,15,16]; (2) assuming that the air pressure in the void spaces of an unsaturated soil slope is equal to the atmospheric pressure [9,17,18]; (3) applying a two-phase fluid (water and air) flow [19][20][21][22][23]; and (4) considering hydraulic hysteresis, including the effects of capillarity and/or air entrapment, reflecting different hydraulic states under wetting and drying conditions [24,25]. Such physically based numerical studies have mainly been applied at slope or watershed scales.…”

Section: Introductionmentioning

confidence: 99%

Effects of Two-Phase Flow of Water and Air on Shallow Slope Failures Induced by Rainfall: Insights from Slope Stability Assessment at a Regional Scale

Kang

Cho

Kim

et al. 2020

Water

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Over 160 shallow landslides resulted from heavy rainfall that occurred in 26–27 July 2011 at Umyeon Mountain, Seoul, South Korea. To accurately reflect the fluid flow mechanism in the void spaces of soils, we considered the two-phase flow of water and air for rainfall infiltration analysis using available historical rainfall data, topographic maps, and geotechnical/hydrological properties. Variations in pore water and air pressure from the infiltration analysis are used for slope stability assessment. By comparing the results from numerical models applying single- and two-phase flow models, we observed that air flow changes the rate of increase in pore water pressure, influencing the safety factor on slopes with a low infiltration capacity, where ponding is more likely to occur during heavy rainfall. Finally, several slope failure assessments were conducted to evaluate the usefulness of using the two-phase flow model in forecasting slope stability in conditions of increased rainfall sums. We observed that the two-phase flow model reduces the tendency of over-prediction compared to the single-phase model. The results from the two-phase flow model revealed good agreement with actual landslide events.

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“…where b and c are the constants for water and air, respectively, which are both equal to 0.5 [36]. The van Genuchten-Mualem (vG-M) relative permeability model was widely applied to the infiltration analysis in previous research [15,21,24,27,36,38] because it can be easily derived directly using the constant of the van Genuchten SWRC model. However, numerical instability caused by a very steep gradient of the vG-M model in a range of small matric suction values can induce a highly nonlinear solution [39].…”

Section: Unsaturated Flowmentioning

confidence: 99%

Slope Stability Analysis of Unsaturated Soil Slopes Based on the Site-Specific Characteristics: A Case Study of Hwangryeong Mountain, Busan, Korea

2020

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Shallow slope failures occur almost every year during the rainy season. Continuous observation of the meteorological parameters and hydrological characteristics is required to more clearly understand the triggering mechanisms of shallow slope failure. In addition, influential factors, such as type of relative permeability models, air flow, and variation of hydraulic conductivity associated with stress–strain behavior of soil, have significant effects on the actual mechanism of rainfall infiltration. Real-time data including hourly rainfall and pore water pressure in response to rainfall was recorded by devices; then, the change in pore pressure from the devices was compared to the results from the infiltration analysis with applications of three relative permeability models, air flow, and the coupled hydro-mechanical analysis to examine an appropriate site-specific approach to a rainfall infiltration analysis. The infiltration and stability analyses based on the site-specific hydrologic characteristics were utilized to create maps of safety factors that depend on the cumulative rainfall. In regions vulnerable to landslides, rainfall forecast information and safety factor maps built by applying various rainfall scenarios can be useful in preparing countermeasures against disasters during the rainy season.

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Hydraulic hysteresis effects on the coupled flow–deformation processes in unsaturated soils: Numerical formulation and slope stability analysis

Cited by 17 publications

References 67 publications

Stability and characterisation of spoil heaps in European surface lignite mines: a state-of-the-art review in light of new data

Stability and characterisation of spoil heaps in European surface lignite mines: a state-of-the-art review in light of new data

Effects of Two-Phase Flow of Water and Air on Shallow Slope Failures Induced by Rainfall: Insights from Slope Stability Assessment at a Regional Scale

Slope Stability Analysis of Unsaturated Soil Slopes Based on the Site-Specific Characteristics: A Case Study of Hwangryeong Mountain, Busan, Korea

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