Evaluation of Leaching Behavior of Treated and Untreated Gypseous Soil

Al-Gharbawi, Ahmed S. A.; Fattah, Y.M.; Mahmood, Mohsin

doi:10.1088/1755-1315/856/1/012050

Cited by 8 publications

(4 citation statements)

References 2 publications

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“…The results indicate that gypsum (χ) is the predominant element in the gypseous soil, accounting for approximately 44.7-45.3%. Similar findings were reported by Al-Gharbawi [36] and Zidan and Hussein [37]. In natural or slightly unsaturated soil, the high calcium carbonate content (the primary form of carbonate in gypseous soil) suggests a lower clay mineral content and higher shear strength.…”

Section: Physical and Chemical Propertiessupporting

confidence: 86%

Studying Characteristics and Strength of the Unsaturated Gypseous Soil with Various Saturation Degrees

Abood,

Fattah,

Al-Adili

2023

ETJ

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Tests on gypseous soil include standard Proctor compactions and consolidated undrained triaxial compression.• The soil was either natural, unsaturated at degrees of saturation (30%, 60%, and 80%), or fully saturated. • Increasing the humidity of the gypseous soil at saturation degrees causes a decline in the internal friction angle. • The soil cohesion for effective and total stress increased with gypseous soil moisture up to (60%) saturation degree.The main objective of this study is to determine the appropriateness of unsaturated gypseous soil as a subgrade layer for carrying foundations. A comprehensive laboratory testing program was implemented to investigate the geotechnical characteristics and behavior of unsaturated gypseous soil. Tests that are physical included specific gravity, classification tests, relative density, Proctor compactions, single and double oedometer collapse potential, and static triaxial compression (CU-test). Chemical testing, Scanning Electron Microscopy (SEM), and Electronic Dissipation x-ray Scanning (EDS) analyses were also carried out.The tests were performed for samples prepared at 70% relative density of the natural gypseous soil. Tests are performed on the natural, unsaturated at degrees of saturation (30%, 60%, and 80%) and fully saturated gypseous soil to investigate the gypseous soil behaviors. In both single and double oedometer testing, it was discovered that the degree of specimen collapse is (Moderate) at 70% relative density, with a collapse index value ranging from (4%). The angle of internal friction for both total and effective stresses (φ' and φ) decreases as the moisture content of the gypseous soil increases at all saturation levels. In contrast, it was found that the strength of soil cohesion for both total and effective stresses (c' and c) increased with increasing gypseous soil moisture up to saturation (60%), which led to a rise in soil shear strength. The reduction value ranged from (38.50° to 7°) in respect of effective stresses and between (34.50° and 7°) with respect to total stresses. Effective stress increase varied from (10.0 -26.0 kPa), and total stress increase ranged from (12.50 -28.0 kPa). Then the strength started gradually decreasing at the saturation degrees 80 and 100%, respectively. As a result, the shear strength of the soil decreases with the value of reduction ranging from (20.0 -11.50 kPa) for effective stresses and (21.50 -11.50 kPa) for total stresses.

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Section: Physical and Chemical Propertiessupporting

confidence: 86%

Studying Characteristics and Strength of the Unsaturated Gypseous Soil with Various Saturation Degrees

Abood,

Fattah,

Al-Adili

2023

ETJ

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“…These changes may create adverse problems for the structures founded on such soils. The water flows into the soil may cause one or more of: particle movement, compression due to seepage forces, and removal of chemicals, colloids, and microorganisms [15], and [16].…”

Section: Dissolution Of Gypsum and Formation Of Sinkholesmentioning

confidence: 99%

Mosul dam issues: analysis of the problem based on several studies

Obead

Fattah

2022

IOP Conf. Ser.: Earth Environ. Sci.

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Mosul Dam is the Middle East’s second-largest dam in terms of reservoir capacity. Since its inception in 1986, this dam has been plagued by seepage difficulties in its base caused by the breakdown of gypsum. Underneath the foundation, there are strata of anhydrite. This occurrence has sparked worry the dam’s stability. This paper presents a survey of studies conducted by several researchers on concerns related to the stability and safety of the Mosul Dam in Iraq. Additionally, the implications of the dam breach scenarios are to be presented and discussed. In another word, the Mosul Dam issues are assessed with different references to geologic challenges of the abutments and foundation, dissolution of gypsum and formation of sinkholes, dissolution of gypsum and seepage, and the probable scenarios for concerns of dam failure. After the ISIS conflict, maintenance has been disrupted and signs at the dam have triggered renewed concerns. Consequently, the Iraqi government have contracted the Italian engineering company Trevi to start remedial work on the dam. This work was in 2016. Therefore, the present state of Mosul Dam was declared as safe and stable.

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“…Leaching appeared to have an impact on the geotechnical parameters, increasing the sand percentage, void ratio, and coefcient of permeability. It was discovered that soaking gypseous soils in brine doubles the collapse potential compared to pure water that the permeability coefcient of the oedometer shows lower results than the modifed leaching, and the permeability coefcient of the modifed permeability test is more believable results than the permeability test of the oedometer [12]. Te elimination of soluble salts and dissolved materials alters the soil's physicochemical and mechanical qualities.…”

Section: Introductionmentioning

confidence: 99%

“…Te procedure happens by difusion or a hydraulic gradient. Gypseous soils experience a number of changes in their features as a result of their ongoing mass loss, as well as changes in the constituent materials' properties brought on by leaching and the elimination of bond strength connecting sand grains [12].…”

Section: Introductionmentioning

confidence: 99%

Collapsibility of Gypseous Soil Treated with Pectin-Biopolymer through Leaching

Hussein

Muhauwiss

Abdul-Jabbar

2023

Journal of Engineering

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Gypsum reinforcement in dry soil provides activity resistance. It quickly becomes a source of danger in the conditions of partial and complete soaking of gypsum soil as a result of the dissolution of gypsum, which poses a great danger to the structures built on this soil. The danger increases when water flows through it and works to leach the soil, which leads to the loss of its mass by leaching gypsum. The soil is chemically and mechanically improved to enhance its geotechnical properties, but despite its great advantages in strengthening, it has significant negative effects on the ecosystem, so the use of environmentally friendly materials is essential. Pectin was selected as an improved biopolymer and added at three different contents (0.5, 1, and 2)% to create a soil mixture and at four different gypsum contents (10, 20, 40, and 62%) to evaluate the chemical and mechanical properties of the improved mixture. Develop an engineering model to leach the soil and pectin mixture. The results showed a significant decrease in CH and CP. values due to biogel encapsulation of soil particles and pore filling properties. The percentage decrease in the values of (CH) reaches (0.67, 73, 75, and 68%) for soils 1, 2, 3, and 4, respectively. After soil (1, 2, 3, and 4), CP values decreased in percent (0.63, 0.63, 0.65, and 0.7%). TDS decreased at a biopolymer content of 2% from 1050, 1200, 2200, and 2500 mg/ml to 320, 540, 468, and 570 mg/ml of soils 1, 2, 3, and 4, respectively.

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Evaluation of Leaching Behavior of Treated and Untreated Gypseous Soil

Cited by 8 publications

References 2 publications

Studying Characteristics and Strength of the Unsaturated Gypseous Soil with Various Saturation Degrees

Studying Characteristics and Strength of the Unsaturated Gypseous Soil with Various Saturation Degrees

Mosul dam issues: analysis of the problem based on several studies

Collapsibility of Gypseous Soil Treated with Pectin-Biopolymer through Leaching

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