Effect of compaction state on the soil water characteristic curves of sand–natural expansive clay mixtures

Elkady, Tamer Y.; Al-Mahbashi, Ahmed M.; Dafalla, Muawia; Al‐Shamrani, Mosleh

doi:10.1080/19648189.2015.1112844

Cited by 26 publications

(16 citation statements)

References 23 publications

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“…The soil water characteristic curve which plots moisture versus suction indicates drying trends which can be either unimodal or bimodal. Elkady et al [5] stated that the air entry value and residual water content were observed to increase with the increase in clay content signifying an increase in water retention capacity. They suggested that the bimodal form of the SWCC indicates the presence of two levels of pore sizes, namely, macropores and mesopores/micropores.…”

Section: Resultsmentioning

confidence: 99%

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Trends of Moisture and Electrical Conductivity in Clay Liners

2018

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This research is aimed at investigating the influence of ambient air temperature on the moisture content and electrical conductivity of clay sand mixtures. Volume changes as a result of shrinking or swelling are very much related to the moisture content and the electrical conductivity for liners consisting of sand and clays. The laboratory tests carried out for clay sand mixtures subjected to drying indicated a bilinear trend for 15, 20, 25, and 30% clay content. Moisture content measurements are influenced by the ambient temperature and exposure time. Watering a clay sand layer at a regular frequency in a field site revealed useful information on the trends of moisture gain and loss. Suction fluctuation associated with these changes is responsible for absorbing variable amounts of water. Moisture/Temp/EC sensors (5TE) were utilized to survey a sand clay liner section over 30 day's period. A metrological station installed within the site was used to observe temperature, humidity, and rain fall. The drop of moisture and electrical conductivity was found to be nonlinear with temperature changes and reflecting the bimodal nature of the soil. The general trends of repeated wetting and drying were found similar in shape.

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Section: Resultsmentioning

confidence: 99%

“…The clay selected for use in the liner was obtained from the city of Al-Qatif (Saudi Arabia, Eastern province). Elkady et al [5] stated that Al-Qatif clay is highly expansive and rich in smectite minerals including montmorillonite (>50%). Al-Qatif clay has a liquid limit of 140 and a plasticity index of 95.…”

Section: Materials and Experimental Programmentioning

confidence: 99%

Trends of Moisture and Electrical Conductivity in Clay Liners

2018

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“…The expansive clay used was obtained from the city of Al-Qatif (eastern province of Saudi Arabia). Al-Qatif clay was characterized as highly expansive soil due to high montmorillonite mineral content [30]. Samples of Al-Qatif expansive clay were airdried, pulverized and sieved using sieve No.40.…”

Section: Methodsmentioning

confidence: 99%

“…The input data for HYDRUS-2D modeling is taken from the experimental work on Sand-Clay Mixture ( [30] and [29] ) such as permeability and retention curve data, the climatic data for 90 days (winter period) was taken as a case for Al-Hassa, Saudi Arabia obtained from the Presidency of Metrology and Environment, Saudi Arabia, (Fig. 1).…”

Section: Soil Liner Layoutmentioning

confidence: 99%

Study of Water Flow and Retention in Clay-Sand Liners

Dafalla

Al-Mahbashi

2018

GEOMATE

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This research paper presents a simulation study to predict the percolation of water through soil liners using numerical modeling with HYDRUS-2D. The soil liners included compacted clay/sand mixtures of 0 to 25% clay at 5 to 30 cm thickness. The cumulative water flux or hydraulic barrier at drain layer at the end of simulation period reached a ratio of 0.81, 0.54, 0.29 and 0.09 of water flux at a top profile with no soil liner. The soil liners of 25 and 30 cm thickness with 20% and 15% clay had lesser percolation or water flux at drain layer by about 0.21 and 0.44 compared to water flux at top layer with no soil liner. Using a modeling approach efficient liner systems can be designed for use in water harvesting projects or landfill covers. The modeling and simulation are dependent on the hydraulic conductivity of the compacted soil liner, soil water characteristics curves as well as irrigation and rainfall rates.

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“…The volumetric water content and permeability coefficient are constant when the slide mass is in a saturated state. However, they should be determined through laboratory experiments when the slide mass is in an unsaturated state [44]. It is difficult and time-consuming to measure the SWCC for the unsaturated soil using laboratory tests.…”

Section: Geomechanical Model Of the Sifangbei Landslidementioning

confidence: 99%

Stability Analysis of Hydrodynamic Pressure Landslides with Different Permeability Coefficients Affected by Reservoir Water Level Fluctuations and Rainstorms

Huang

Luo

Liu

2017

Water

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Abstract:It is significant to study the variations in the stability coefficients of hydrodynamic pressure landslides with different permeability coefficients affected by reservoir water level fluctuations and rainstorms. The Sifangbei landslide in Three Gorges Reservoir area is used as case study. Its stability coefficients are simulated based on saturated-unsaturated seepage theory and finite element analysis. The operating conditions of stability coefficients calculation are reservoir water level variations between 175 m and 145 m, different rates of reservoir water level fluctuations, and a three-day continuous rainstorm. Results show that the stability coefficient of the hydrodynamic pressure landslide decreases with the drawdown of the reservoir water level, and a rapid drawdown rate leads to a small stability coefficient when the permeability coefficient ranges from 1.16 × 10 −6 m/s to 4.64 × 10 −5 m/s. Additionally, the landslide stability coefficient increases as the reservoir water level increases, and a rapid increase in the water level leads to a high stability coefficient when the permeability coefficient ranges from 1.16 × 10 −6 m/s to 4.64 × 10 −5 m/s. The landslide stability coefficient initially decreases and then increases as the reservoir water level declines when the permeability coefficient is greater than 4.64 × 10 −5 m/s. Moreover, for structures with the same landslide, the landslide stability coefficient is most sensitive to the change in the rate of reservoir water level drawdown when the permeability coefficient increases from 1.16 × 10 −6 m/s to 1.16 × 10 −4 m/s. Additionally, the rate of decrease in the stability coefficient increases as the permeability coefficient increases. Finally, the three-day rainstorm leads to a significant reduction in landslide stability, and the rate of decrease in the stability coefficient initially increases and then decreases as the permeability coefficient increases.

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Effect of compaction state on the soil water characteristic curves of sand–natural expansive clay mixtures

Cited by 26 publications

References 23 publications

Trends of Moisture and Electrical Conductivity in Clay Liners

Trends of Moisture and Electrical Conductivity in Clay Liners

Study of Water Flow and Retention in Clay-Sand Liners

Stability Analysis of Hydrodynamic Pressure Landslides with Different Permeability Coefficients Affected by Reservoir Water Level Fluctuations and Rainstorms

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