State of practice for use of the soil-water characteristic curve (SWCC) in geotechnical engineering

Fredlund, D. G.

doi:10.1139/cgj-2018-0434

Cited by 45 publications

(15 citation statements)

References 27 publications

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“…Research activities are focused mainly on frost heaves (Long et al, 2018;Wang et al, 2014;Zhou et al, 2018), water freezing in porous materials (Kou et al, 2018;Lu et al, 2019;Zhang & Liu, 2018;Bąk & Chmielewski, 2019), thermal-technical parameters of soils and building materials (He et al, 2017;Kömle et al, 2007Kömle et al, , 2010Gnip et al, 2001). Significant results of Canadian research (Fredlund, 2019;Pentland, 2000;Soliman et al, 2008;Tam, 2009) led to the development of the SoilVision software (Fredlund, 2011) which addresses various problematic processes occurring in soils. One of these complex processes is the thermal regime of soil, which can be mo-delled in the software using the SVHeat program product (Thode, 2012).…”

Section: Introductionmentioning

confidence: 99%

Numerical Modelling of Thermal Regime of Railway Track - Structure With Thermal Insulation (Styrodur)

Ižvolt

Dobeš

Holešová

et al. 2021

Journal of Civil Engineering and Management

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This paper presents the results of numerical modelling of the influence of various factors (geometrical layout of the structural layers of the railway track, climatic factors and ballast fouling) on the freezing of railway track structure with a built-in thermal insulation layer of extruded polystyrene (Styrodur). At the same time, the suitability and expediency of incorporating the thermal insulation layer at the sub-ballast upper surface level (i.e. below the rail ballast construction layer), or at the level of subgrade surface are discussed. Numerical modelling results in the main factors that should be taken into account in the dimensioning of the sub-ballast layers with a built-in thermal insulation layer. Based on the data on the depth of freezing of the railway track structure obtained from numerical modelling, a design nomogram for dimensioning was created and subsequently the influence of the changes of climatic characteristics on the freezing of the railway track structure was then mathematically expressed.

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Section: Introductionmentioning

confidence: 99%

Numerical Modelling of Thermal Regime of Railway Track - Structure With Thermal Insulation (Styrodur)

Ižvolt

Dobeš

Holešová

et al. 2021

Journal of Civil Engineering and Management

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“…The hysteretic cycles of water content with respect to soil water potential in the unsaturated soil behaviour are highlighted. Many authors recently focused on the same aspect, under the experimental point of view (Tami et al 2004;Yang et al 2012;Rianna et al 2014;Pirone et al 2014;Bovolenta et al 2020;Liang 2020) or by proposing different solutions to model this natural phenomenon (Li 2005;Comegna et al 2016b;Fredlund 2019;Chen et al 2019;Wei et al 2020). Bordoni et al (2017) already investigated how to improve the estimation of complete field SWCCs based on field data acquired at Montuè test site on a time lapse of 5 years (Bordoni et al 2015).…”

Section: Introductionmentioning

confidence: 99%

“…This last aspect is treated under a twofold perspective with respect to other similar researches. First of all, the detailed monitoring of the hydraulic behaviour in different thin soil sub-layers aims at showing that it may not always be appropriate modelling the behaviour of a shallow soil in the first two meters from ground level using only a single SWCC, even though the soil appears homogeneous in terms of geotechnical characteristics (Comegna et al 2016b;Fredlund 2019). Secondly, the data acquired in the field experimentally confirm what has been observed by other authors on the rain infiltration into the shallow soil, i.e.…”

Section: Introductionmentioning

confidence: 99%

Observations on soil-atmosphere interactions after long-term monitoring at two sample sites subjected to shallow landslides

Bordoni

Bittelli

Valentino

et al. 2021

Bull Eng Geol Environ

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Soil-atmosphere interaction has implications in different scientific research contexts and is increasingly investigated through field measurements. This paper reports a detailed description of interaction between shallow soil and atmosphere at two test sites in Oltrepò Pavese area (Northern Italy). The two test sites are in the same climatic area but are characterised by different geological features. In fact, the first objective is to compare the behaviour of two different soils, namely a clayey-sandy silt (CL) and a silty clay (CH), under similar meteorological events. Soil-atmosphere interaction is studied on the basis of long-term (about 87 and 42 months for the two test sites, respectively) monitoring data of both volumetric water content and soil water potential, recorded at different depths along two vertical soil profiles in the first two metres from ground level. Field measurements, together with meteorological data such as precipitation and air temperature, allow for clear identification of the seasonal fluctuations of unsaturated soil hydraulic properties. To infer detailed information, the recorded data were processed and relationships between soil water potential and water content were investigated. Different time spans, from several months to a few days, even including single rainy events, are considered to show the hydraulic soil behaviour. The hysteretic cycles of water content with respect to soil water potential and non-equilibrium flow are highlighted. In particular, the measured soil water potential is in the range of 0–800 kPa and of 0–1500 kPa for the CL and CH soil, respectively. At both sites, the observed hysteretic cycles are more frequent in the hot season (summer) than in the cold season (winter) and tend to reduce with depth. The experimental results are compared with the soil water characteristic curves (SWCCs) to assess whether and to what extent the SWCCs are reliable in modelling the hydraulic behaviour of partially saturated soils, under atmospheric forcing, at least in the considered climatic contexts.

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“…Nevertheless, even if various research achievements evidence the benefit of considering unsaturated soil concepts and procedures in geotechnical design analyses (e.g. [3]), they are rarely used in standard practice. A good example of the current gap between research and practice is represented by earthen infrastructures, as river and road embankments, which are generally located above the groundwater level and typically in partially saturated conditions during their lifetime; despite this, their response to external actions (hydraulic and climatic boundaries variations) is generally determined neglecting the effect of negative pore-water pressures.…”

Section: Introductionmentioning

confidence: 99%

Shear strength and retention models of a partially saturated riverbank silty soil

et al. 2020

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Soil mechanical behaviour is strictly related to its natural water content, which is primarily dependent on hydraulic boundary conditions. When soils are partially saturated, as frequently occur in river embankments, soil suction also turns into a fundamental variable worth of investigation and monitoring, both in laboratory and in the field, for a reliable interpretation of the related soil response to external actions. The case of earthen water retaining structures and their safety condition assessment towards local or global collapse mechanisms requires special attention for soil characterization and site measurement of unsaturated soil states. Moreover, strength and hydraulic models used for relevant stability analyses should be adequate for representing the site-specific behaviour of soil in terms of water content, pore water pressure and suction values, relying on the effective possibility to properly calibrate all required parameters. Nevertheless, these aspects typically receive only limited attention, especially in standard practice, leading to inaccurate estimates of flood hazard and related risk management. In this context, with the aim of comprehensively studying the strength and retention properties of a riverbank silty soil, a series of laboratory investigations – including oedometric and direct shear tests under suction-controlled conditions – have been performed. Laboratory tests are here used as the main direct source of information to model unsaturated soil behaviour, monitoring different state variables under suction-controlled conditions. The results have been then interpreted using both literature and soil-specific mechanical and hydraulic models, to be possibly implemented in integrated methodologies for the stability assessment of river embankments.

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State of practice for use of the soil-water characteristic curve (SWCC) in geotechnical engineering

Cited by 45 publications

References 27 publications

Numerical Modelling of Thermal Regime of Railway Track - Structure With Thermal Insulation (Styrodur)

Numerical Modelling of Thermal Regime of Railway Track - Structure With Thermal Insulation (Styrodur)

Observations on soil-atmosphere interactions after long-term monitoring at two sample sites subjected to shallow landslides

Shear strength and retention models of a partially saturated riverbank silty soil

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