Engineering and Technology Journal

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

Ahmed S. Abood; Mohammed Y. Fattah; Aqeel S. Al-Adili

Volume 41, Issue 11 , November 2023, , Page 1309-1324

https://doi.org/10.30684/etj.2023.140119.1453

Abstract

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 ... Read More ... 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 (f' and f) 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.

Investigation of the Bearing Capacity and Collapsibility of Gypseous Soil Using Geotextile Reinforcement

Qasim A. Al-Obaidi; Makki K. Mohsen; Ayad O. Asker

Volume 40, Issue 5 , May 2022, , Page 792-801

https://doi.org/10.30684/etj.2021.131076.1002

Abstract

This study aims to increase the bearing capacity of the soil by using geosynthetics in a single, double, or triple distribution pattern. The gypseous soil samples were brought from ... Read More ...

Variation of Matric Suction as a Function of Gypseous Soil Dry Density

Hussein H. Karim; Qasim A. Al-Obaidi; Ali A. Al-Shamoosi

Volume 38, 6A , June 2020, , Page 861-868

https://doi.org/10.30684/etj.v38i6A.550

Abstract

Gypseous soil is one of the most problematic types of collapsible soils which is affected by many geotechnical factors. The most important factors are the effect of loading and wetting ... Read More ...

Behavior of Piled Raft Foundation Model Embedded within a Gypseous Soil Before and after Soaking

N.A. Ab-dullah; M.R. Mahmood; H.H. Baqir

Volume 35, 5A , May 2017, , Page 445-455

https://doi.org/10.30684/etj.35.5A.3

Abstract

The paper explain an experimental study to show piled raft system behavior when embedded within gypseous soil in three different stats (dry, socking for 1 day and placing a bearing ... Read More ...

Study The Effect of Al-Sugar Factory’s Waste on The Engineering Properties of Gypseous Soil

K.N. Al-safaar; Anas. F.K; A.M. Ialkiki

Volume 32, Issue 8 , August 2014, , Page 292-303

https://doi.org/10.30684/etj.32.8A20

Abstract

This study investigates the possibility of using the industrial waste material of Al-sugar factory to improve the engineering properties of Gypseous Soil which taken from Baiji area. ... Read More ...

Assessing the Dynamic Behavior of Asphalt Stabilized Gypseous Soil

Mahmood D. Ahmed

Volume 32, Issue 4 , May 2014, , Page 822-841

https://doi.org/10.30684/etj.32.4A.3

Abstract

The study presents the test results of stabilizing gypseous soil embankment obtained from Al- Faluja University Campus at Al-Ramady province. The laboratory investigation was divided ... Read More ... The study presents the test results of stabilizing gypseous soil embankment obtained from Al- Faluja University Campus at Al-Ramady province. The laboratory investigation was divided into three phases, the physical and chemical properties; the optimum liquid asphalt (emulsion) requirements (which are manufactured in Iraq) were determined by using one dimensional unconfined compression strength test. In the first phase , the optimum fluid content was 11% (6% of emulsion with 5% water content). At phase two, the effect of aeration technique was investigated using both direct shear and permeability test. At phase three, a laboratory soil model of dimensions 50x50x30 cm was used as a representative of gypseous soil; pure soil, and asphalt stabilized soil have been compacted in five layers after practicing an aeration technique at maximum dry density (modified compaction) cyclic loading test was carried out on four gypseous soil models, two of them were pure soil under (dry and absorbed condition), and the other two were stabilized with emulsion also under (dry and absorbed condition). The impact of charging the hydraulic conductivity due to asphalt stabilization was investigated and the vertical deformations were determined using LVDT. For the pure soil in dry condition the vertical settlement at the top surface was (7.45 mm) at (157 load cycles), while for pure soil model under absorbed condition, the water was raised to the surface in three days , so the vertical settlement at the top surface was (12.5 mm) at (29 load cycles), this means that the pure gypseous soil under absorbed condition show reduction in strength by(85%). When the stabilized soil is in dry condition, the vertical settlement at the top surface was (9.75 mm) at (911 load cycles), while the soil was stabilized and subjected to water absorbed for seven days. The water stopped rising at second layer which is the same inlets level from the bottom, and the vertical settlement was (10.47 mm) at (897 load cycles), so there is no change in strength at failure.

Prediction of Square Footing Settlement under Eccentric Loading on Gypseous Soil through Proposed Surface for Dry and Soaked States

Bushra S. Z. Albusoda; Abdul-Kareem E; R. S.Hussein

Volume 31, Issue 20 , November 2013, , Page 217-237

https://doi.org/10.30684/etj.2013.83797

Abstract

Gypseous soils as any other soils deform under loading, this deformation differs greatly between its dry state and its soaked state. This deformation also differs when the loading is ... Read More ...

Stability Behavior of Lime Stabilized Gypseous Soil

Abdulrahman Aldaood; Marwen Bouasker; Amina A Khalil; Ibrahim Al-Kiki

Volume 31, Issue 20 , November 2013, , Page 324-338

https://doi.org/10.30684/etj.2013.83803

Abstract

In arid and semi-arid zones, gypsum (CaSO4.2H2O) is one of the soluble of the common minerals that found in soils. In Iraq, gypseous soils is a worldwide stability problem that causes ... Read More ...

Study Shear Strength Characteristics of Gypseous Sandy Soil Using Additives

Hussein H. Karim; T. Schanz; Maha H. Nasif

Volume 31, Issue 8 , June 2013, , Page 1431-1446

https://doi.org/10.30684/etj.31.8A1

Abstract

The present study investigated the possibility of enhancing collapsible gypseous soil of Al-Qarma site (with relatively high gypsum content around 50%), which is located in Al-Anbar ... Read More ...

Improving Collapsibility and Compressibility of Gypseous Sandy Soil Using Bentonite and Kaolinite

Hussein H. Karim; T. Schanz; Maha H. Nasif

Volume 30, Issue 18 , October 2012, , Page 3141-3153

https://doi.org/10.30684/etj.30.18.3

Abstract

The sandy soil which covers the surface layer for the investigated area consists of high gypsum content (50%). The soil was found to be a “collapsible” soil. Thus bentonite ... Read More ...

Improvement of Gypseous Soil by Clinker Additive

Mohammed A. Mahmoud Al-Neami

Volume 28, Issue 19 , September 2010, , Page 5822-5832

https://doi.org/10.30684/etj.28.19.2

Abstract

In this paper, mechanical properties were studied for gypseous soilbrought up from Al-Axandria region, Babylon Governorate. Gypsumcontent is equal to (40%). Many tests were employed ... Read More ...

Artificial Neural Networks Analysis of Treatment Process of Gypseous Soils

Mohammad M. Al-Ani; Mohammad Y. Fattah; Mahmoud T. A. Al-Lamy

Volume 27, Issue 9 , June 2009, , Page 1811-1832

https://doi.org/10.30684/etj.27.9.13

Abstract

Artificial Neural Networks (ANNs) are used to relate the properties of gypseous soilsand evaluate the values of compression of soils under different conditions. Therefore, onelayerperception ... Read More ...

Long -Term Deformation Of Some Gypseous Soils

Mohammed Y. Fattah; Yousif J. al-Shakarchi

Volume 26, Issue 12 , December 2008, , Page 1461-1483

https://doi.org/10.30684/etj.26.12.3

Abstract

Time-dependent deformation and stress relaxation in soils are important in a variety ofgeotechnical problems where long-term behavior is of concern.Previous studies on soils showed ... Read More ... Time-dependent deformation and stress relaxation in soils are important in a variety ofgeotechnical problems where long-term behavior is of concern.Previous studies on soils showed that the magnitude of delayed compression(creep) is controlled by compressibility and soil sensitivity in addition topreconsolidation.In this paper, the time-dependent behavior of gypseous soils is investigated. Thesoils used in this study were brought from three locations at Al-Tar region west of Al-Najaf city in Iraq. These soils had gypsum content of (66%, 44% and 14.8%). Themineralogical and chemical properties of the soils were determined.Two series of tests were performed. In the first, collapsibility characteristics wereinvestigated for a long period (60 days) by conducting single and double oedometertests. In the second series, the effect of relative density on collapse with time wasinvestigated. The samples were compacted to 40%, 50% and 60% relative density andthen tested. The results of collapse tests showed that the relationship between thestrain and logarithm of effective stress has two vertical lines. The first one representsthe collapse settlement taking place within 24 hours, while the second one representsthe long-term collapse. The collapse potential in both single and double oedometertests increases when the gypsum content increases from (14.8%) to (66%) and whenthe initial void ratio increases.The results of double oedometer tests showed that the relationship between thecollapse potential and logarithm of time, for samples loaded to 800 kPa for 60 days,consist of three distinct segments. The first segment is represented by a curve concavedownward in which the compressibility gradually increases. The second segment is astraight line with a higher increase in the strain. The third segment which refers tocreep collapse depends on the gypsum content. Gypseous soil with low gypsumcontent (14.8%) exhibited significant decrease (5.21% at 24 hours to 7.16% at 60 days)in collapse potential with time.

CONTRIBUTION OF LIQUID ASPHALT IN SHEAR STRENGTH AND REBOUND CONSOLIDATION BEHAVIOUR OF GYPSEOUS SOIL

SAAD I. SARSAM; SALAH W. IBRAHIM

Volume 26, Issue 4 , April 2008, , Page 484-495

https://doi.org/10.30684/etj.29.4.10

Abstract

AbstractThis paper deals with the effect of stabilizing gypseous soil using two liquid Asphalttypes (cutback and emulsion) on its behavior in shear strength and reboundconsolidation.Soil-Asphalt ... Read More ...

Keywords = Gypseous soil

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