Nature of Soil–Water Characteristic Curve for Plastic Soils

Marinho, Fernando A. M.

doi:10.1061/(asce)1090-0241(2005)131:5(654)

Cited by 60 publications

(34 citation statements)

References 26 publications

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“…It is noted that this tendency exists for both total and matric suction, however, for the total suction, this correlation has a higher value of R 2 (0.71). It is interesting to analyze the difference (D) in suction in relation to soil plasticity because plasticity can provide an approximate estimation of soil suction [8]. Fig.3 presents the obtained results in terms of the maximum difference (D) against the liquid limit (LL) of soil.…”

Section: Resultsmentioning

confidence: 99%

Effect of Gravel Content on Soil Suction

Liu¹

2017

GEOMATE

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This paper seeks to a) investigate the effect of gravel on soil suction and b) establish whether results of standard suction tests using filter paper can accurately represent the value of suction that would be expected in the field. Eight natural soils with different soil gradation and plasticity were used to prepare two types of specimens: a) the "original" specimens (no change compared to the field soil), and b) "sieved" specimens -when the "original" soil was passed through a 2-mm sieve to meet the standard requirement. Comparisons of soil-water characteristics curves (SWCC) obtained for both types of specimens were made to better understand the effect of gravel content on total and matric suction. The obtained data indicated that the results of standard tests can significantly overestimate the soil suction. In particularly, it was found that as the gravel content increased from 4.8 to 19.6%, the difference in suction between the "original" and "sieved" specimens increased to 14% (total suction) and almost 20% (matric suction). The experimental data showed that the effect of gravel was more pronounced for low plasticity soils, compared to high and very high plasticity soils, in which the influence of gravel on suction was found to be insignificant. Although the "sieved" specimens tended to produce higher values of suction, this tendency might reverse for high and very high plasticity soils when their liquidity index (LI) became positive.

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Section: Resultsmentioning

confidence: 99%

Effect of Gravel Content on Soil Suction

Liu¹

2017

GEOMATE

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“…The soil-water characteristic curve for the Malda soil is determined by following the standard test method [2,25] using tensiometers. The soil was first dried and then known amount of water is added to it.…”

Section: Soil-water Characteristics Curve (Swcc)mentioning

confidence: 99%

“…The rainfall intensities considered in this study are 2,4,8,16,25, and 32 mm/h. For each case, the rainfall infiltration rate is computed from the rainfall intensity and the duration of the rainfall, and applied as a boundary flux across the slope.…”

Section: Water Table Fluctuation and Reduction Of Suction Pressure Wimentioning

confidence: 99%

Rain-triggered slope failure of the railway embankment at Malda, India

Raj

Sengupta

2014

Acta Geotech.

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The common slope stability analysis is incapable of accurately forecasting shallow slides where suction pressures play a critical role. This realization is used for elaborate stability analyses which include soil suction to better predict rainfall-induced slides at railway embankment at Malda where three known cases of slope failures and train derailments occurred after heavy rainfall. The relationship between the soil-water content and the matric suction is established for the embankment soil. It is then used in the coupled analyses of seepage and slope stability to estimate performances of the embankment at different intensity and duration of rainfall. The numerical simulations are performed with the FE code Geo-Studio. The numerical results show significant reduction in the factor of safety of the railway embankment with the increase in the intensity and duration of rainfall. The effectiveness of the proposed mitigation measures including placement of 2 m-wide free draining rockfill across the slopes and drilling 5-m-long sheet pile wall at the toe of the embankment is studied numerically. The study confirms that the proposed mitigation measures effectively increase the factor of safety of the embankment and stabilizing it even in case of a heavy rainfall of 25 mm/h over 12 h.

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“…Beyond this air entry into the pore space, the soil suction is steadily increasing, with reducing volumetric water content. In the case of extremely high soil suction, the volumetric water content approaches a residual water content, θ R , at which water is not further drained out and is held in the soil matrix by adsorptive forces to the particle surface [61]. In contrast to the IDC, the IWC starts at dry condition, with water content close to zero.…”

Section: Swccmentioning

confidence: 99%

“…At soil-water phase state equilibrium, hydraulic stress is described by negative pore water pressure [77,80]. For instance, volume reduction occurs under soil desiccation due to the suction-induced capillary forces [26,51,61,81]. The capillary rise of water during desiccation implies a contractile force exerted by the curved meniscus at the interface of the air and water phase [82].…”

Section: External Stress and Internal Stressmentioning

confidence: 99%

Mechanical, hydraulic, and dielectric characterisation of fine-grained soils during densification

Schwing¹

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Soil characterisation is of primary interest for several disciplines, including geotechnical and geo-environmental engineering, soil science, and agriculture. An upcoming and promising method for soil characterisation relies on the high-frequency electromagnetic measurement technique which provides the potential to explore and investigate soils. However, successful application of this technique requires a profound understanding of the multi-physical processes arising from interactions between soil as a porous medium and the propagation of electromagnetic waves. This thesis focuses on a coupled experimental investigation of the mechanical, hydraulic, and dielectric characterisation of fine-grained soil during densification.In the framework of this thesis, the following steps have been completed and novel findings have been made:1. Probe designs have been developed, modified and improved to measure the dielectric soil properties in a frequency range from 1 MHz to 3 GHz during shrinkage and compaction. A low-cost in-house-manufactured probe was introduced, which was specifically designed for standardised geotechnical soil shrinkage test. During preliminary investigations, the calibration procedure and performance of these sensors were experimentally and numerically tested. The results showed agreement in the targeted frequency window.2. Compaction and shrinkage tests on fine-grained soils were conducted in combination with dielectric and soil suction measurements. The shrinkage curve and soil water characteristic curve (SWCC) was established and successfully parameterised with physical based models. The complex permittivity was determined in a frequency range from 1 MHz to 3 GHz. The dielectric properties measured during the shrinkage test showed a sudden drop of complex permittivity which could be located in the residual shrinkage zone.3. A theoretical electromagnetic mixture approach was used to model the measured frequency dependent dielectric properties of soils during shrinkage and compaction based on the parameterised shrinkage curve and SWCC. The theoretical results were compared to the dielectric measurements on different fine-grained soils. The comparison ii showed that the real part of permittivity could be well predicted whereas the imaginary part suffered inaccuracies.4. A sensitivity analysis was performed with the theoretical electromagnetic mixture approach in consideration of the shrinkage behaviour and SWCC in order to investigate the influence of soil suction and dry density on the frequency dependent permittivity.The sensitivity analysis showed that the real part of the permittivity near 1 GHz was insensitive to changes in the soil suction and dry density. In the MHz range, the real part of the permittivity was more sensitive to changes in soil suction than it was to dry density. The imaginary part of the permittivity was generally observed to be more sensitive to soil suction over the entire frequency range.

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Nature of Soil–Water Characteristic Curve for Plastic Soils

Cited by 60 publications

References 26 publications

Effect of Gravel Content on Soil Suction

Effect of Gravel Content on Soil Suction

Rain-triggered slope failure of the railway embankment at Malda, India

Mechanical, hydraulic, and dielectric characterisation of fine-grained soils during densification

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