scholarly journals Reducing Settlement and Collapse of Gypseous Soil Using Geotextile Reinforcement

2022 ◽  
Vol 961 (1) ◽  
pp. 012050
Author(s):  
Makki K. Mohsen ◽  
Qasim A. Al-Obaidi ◽  
Ayad O. Asker
Keyword(s):  
Model Test ◽  
Soil Structure ◽  
Soil Stabilization ◽  
Reduction Factor ◽  
Test Configuration ◽  
Collapsible Soils ◽  
Gypsum Content ◽  
Unique Model ◽  
Problematic Soils ◽  
Gypseous Soil

Abstract Collapsible soils are problematic soils that have substantial strength while dry but lose strength when wet, resulting in excessive settlements. Soil collapse occurs when increasing moisture weakens chemical or physical connections between soil particles, allowing the soil structure to collapse. The existence of these soils, often with significant gypsum concentration, created serious challenges for structures and major projects. The primary goal of this study is to conduct a series of model tests subjected to static vertical stress to assess the ability of soil stabilization using geosynthetics material by employing single, double, and triple geotextile layers put at various places. A unique model test configuration was employed for this testing. The gypseous soil used was brought from near Sawa Lake by coordinates (31◦18′42.83″N, 45◦00′49.36″E) in Al-Muthanna Governorate. The gypsum content was more than (37%). It was found that, the ultimate bearing capacity of dry and wet gypseous soil models had been determined by using Two Tangent Intersection technique. The results show the Settlement Reduction Factor (SRF) % and the ratio of decreasing the collapse magnitude (Δed )

scholarly journals Physical Properties of Gypseous Soil after Gypsum Removal using EDTA Solution

2018 ◽  
Vol 25 (2) ◽  
pp. 68-73
Keyword(s):  
Soil Structure ◽  
Ground Surface ◽  
Soil Classification ◽  
Granular Soils ◽  
Distilled Water ◽  
Gypsum Content ◽  
Edta Solution ◽  
Before And After ◽  
Different Depths ◽  
Gypseous Soil

The main structural problem in construction on gypseous soils is due to the melting of the gypsum when exposed to water. This may be creating voids in the soil leading to rearrangement of the soil structure and moving the soil particles to more stable positions. This can cause excessive settlement which directly affects superstructures. This study, investigates the influence of gypsum removing on granular soil classification. Four gypsum soil specimens were taken from Al-Qadisiyah district in Tikrit at different depths from the natural ground surface. The depths adopted were 0.75, 1.10, 2.00 and 3.30 m. The corresponding gypsum content was 42.23%, 32.50%, 8.75% and 19.82%, respectively. The EDTA solution was used to disassemble and remove the gypsum particles by washing using distilled water. The results showed that EDTA solution and washing with distilled water was an effective method to remove gypsum from granular soils. Gypsum ratio was reduced to less than 2% in all tested specimens. The percentage of organic matter was not affected, and the specific gravity of the specimens increased between 2% and 12%. The gypsum removal process affected the granular distribution curves of the soil specimens and led to a decrease in the rate of soil grain diameters. In general, classification process of the soil before and after the washing of gypsum from the soil was not affected.

Systematic approach to assessing the applicability of fly-ash-based geopolymer for clay stabilization

2020 ◽  
Vol 57 (9) ◽  
pp. 1356-1368 ◽  
Author(s):  
Hayder H. Abdullah ◽  
Mohamed A. Shahin ◽  
Megan L. Walske ◽  
Ali Karrech
Keyword(s):  
Fly Ash ◽  
Systematic Approach ◽  
Soil Stabilization ◽  
Ground Improvement ◽  
Experimental Program ◽  
Attractive Alternative ◽  
Chemical Additives ◽  
Soil Mineralogy ◽  
Problematic Soils ◽  
Ph Level

Traditional soil stabilization by chemical additives such as cement and lime is a well-established technique for ground improvement of problematic soils. However, with the advantage of lower carbon emission and energy consumption, fly-ash-based geopolymer has recently become an attractive alternative to traditional stabilizers. Nevertheless, the literature lacks systemic approaches that assist engineers to apply this promising binder for soil stabilization, including the proper dosages required for an effective treatment. This paper introduces a systematic approach to assess the applicability of fly-ash-based geopolymer for stabilization of clay soils, through a comprehensive experimental program where engineered and natural clays were examined and evaluated, including soil compaction, plasticity, compressive strength, durability, pH level, and impact of pulverization. The results revealed several factors that influence the level of enhancement of geopolymer-treated clays, including the soil mineralogy, plasticity–activity properties, geopolymer concentration, curing time, and pulverization.

scholarly journals Experimental Pullout Capacity of Screw Piles in Dry Gypseous Soil

2021 ◽  
Vol 318 ◽  
pp. 01002
Author(s):  
Mahdi O. Karkush ◽  
Omar J. Mukhlef
Keyword(s):  
Relative Density ◽  
Offshore Structures ◽  
Pullout Capacity ◽  
Single Screw ◽  
Gypsum Content ◽  
Pullout Testing ◽  
D 20 ◽  
Pile Model ◽  
Supporting Structures ◽  
Gypseous Soil

Screw piles are widely used in supporting structures subjected to pullout forces, such as power towers and offshore structures, and this research investigates their performance in gypseous soil of medium relative density. The bearing capacity and displacement of a single screw pile model inserted in gypseous soil with various diameters (D = 20, 30, and 40) mm are examined in this study. The soil used in the testing had a gypsum content of 40% and the bedding soil had a relative density of 40%. To simulate the pullout testing in the lab, a physical model was manufactured with specific dimensions. Three steel screw piles with helix diameters of 20, 30, and 40 mm are used, with a total length of 500 mm. The helix is continuous over the pile's embedded depth of 400 mm. The results of tests revealed that decreasing the length to diameter (H/D) ratio resulted in a higher pullout capacity of screw piles and a lower corresponding displacement.

scholarly journals Dynamic Response of Single Pile Subjected to Different Frequencies in Gypseous Soil

2020 ◽  
Vol 13 (4) ◽  
pp. 50-57
Author(s):  
Noor D. Abd ◽  
Safa H. AbidAwn
Keyword(s):  
Experimental Study ◽  
Dynamic Response ◽  
Slenderness Ratio ◽  
Vibration Source ◽  
Single Pile ◽  
Collapsible Soil ◽  
Dynamic Movement ◽  
Steel Container ◽  
Gypsum Content ◽  
Gypseous Soil

This paper exhibits an experimental study on dynamic response of a single pile under dynamic load which comes from motor placed on cap pile called a vibration source. This study used the effect of the dynamic movement of vibration on one pile, collapsible soil (gypseous soil) used in this study with 30% gypsum content. The experiment is performed in a dry and soak state. A solid steel pile with a slenderness ratio of 27 was inserted into the soil after preparing it in layers in a steel container (30 * 30 * 60) cm. The test was performed under a dynamic response to the different frequencies 10, 15, 20, and 25 Hz. The results showed that the speed, acceleration and displacement increase with increasing frequency of the vibration source in addition to that the values of speed, acceleration and displacement amplitude are less in the case of soaking compared to their values in the dry state.

scholarly journals Effect of Pile Spacing on Group Efficiency in Gypseous Soil

2019 ◽  
Vol 5 (2) ◽  
pp. 373 ◽  
Author(s):  
Bilal Jabbar Noman ◽  
Safaa H. Abd-Awn ◽  
Hassan O. Abbas
Keyword(s):  
Bearing Capacity ◽  
Load Condition ◽  
Soil Mass ◽  
Deep Foundation ◽  
Collapsible Soil ◽  
Floating Pile ◽  
Group Efficiency ◽  
Gypsum Content ◽  
Group Pile ◽  
Gypseous Soil

As a matter of fact, the gypseous soil is usually considered as collapsible soil, such type of soil illustrates high resistance to settlement and high bearing capacity when it is dry, but it loses these characteristics when it is inundated and collapses excessively because of the sudden decrease in the volume of the surrounding soil mass. It is founded in the arid and semi-arid regions of the world in Asia, South Asia (Iraq, Syria, Jordan, Yemen, and Iran), North Africa, North America, moreover, it covers more than (31%) of the surface area in Iraq. Gypseous soil is one of the most difficult problems facing the process of building any project because of the difficulty of preventing leakage of water to the soil in practice. Deep foundation (piles) are one of the most common types used in collapsible soils which penetrating problematic soil layers and reaching more hard ones (end bearing piles) or transfers loads depending on skin friction (floating pile). The current work is directed to study the behavior of single and group driven pile of square pattern (4 piles) in case of floating pile (friction pile) with different spacing (2D, 4D, 6D) and length to diameter (L/D) ratio of (20) in this special medium dense soil (gypsum content 30% and 61%) under axial load condition. The investigation was carried out to measure the soil collapse before and after inundation. The results showed that the group efficiency for spacing 2D is less than one while for spacing 4D and 6D are more than that value. In addition, the spacing 4D was more efficient to carry 4 group pile in both dry and soaked cases, in addition, the result showed a high reduction in the bearing capacity at inundation state of group pile of (82% in gypsum content 30%) and ( 87% in gypsum content 61%) with respect to dry state.

Influence of Acetic Acid on Gypseous Soil

2020 ◽  
Vol 1002 ◽  
pp. 511-519
Author(s):  
Lamyaa Najah Snodi ◽  
Israa Saleh Hussein
Keyword(s):  
Acetic Acid ◽  
Soil Mass ◽  
Test Results ◽  
Shear Strength Parameters ◽  
Steel Cylinder ◽  
Soaking Time ◽  
Gypsum Content ◽  
Thick Steel ◽  
Laboratory Models ◽  
Gypseous Soil

Gypseous soil disturbed in many regions in the world. Existence of this soil with high gypsum content caused many damages to the buildings and structures that built on it due to dissolve and leaching of the gypsum slates by the flow of water through the soil mass. Therefore, it is necessary to study the properties of such soil. The dissolve of gypsum depends on many factors such as (gypsum content, temperature and other factors). Another important factor which is the acidity of the dissolution liquid must be considered. This study observes the influence of Acetic acid (CH3COOH) on the gypseous soil. Laboratory models includes (270 mm diameter) and (500 mm height) thick steel cylinder container and 17.1 kN/m3 density gypseous soil compacted in three layers, with gypsum content about 58% . The relation between the soaking time and the shear strength parameters was investigated. Also, plastic square container dimensions (250 mm x 250 mm x 300mm) used with same conditions to observed the deformation of the soil. The aim of this study is to simulate the infiltration of Acid in Gypseous soil. Test results show that increase cohesion of soil for diluted acid while decrease cohesion values for concentrated acid. Angle of friction for soil was increase for diluted and concentrated acid.

From the results of the stability of soil structure studies and the physical characteristics of the black meadow soil of the mountain meadow in the limited national park (gorkhi-terelj national park)

2018 ◽  
Vol 22 (03) ◽  
pp. 89-95
Author(s):  
Lkhamsuren B ◽  
Odgerel B ◽  
Purevsuren Sh
Keyword(s):  
Physical Properties ◽  
Vegetation Cover ◽  
National Park ◽  
Soil Structure ◽  
Soil Stabilization ◽  
Meadow Soil ◽  
Mountain Meadow ◽  
Stability And Stabilization ◽  
The Stability ◽  
Properties Of Soil

The study aims to investigate changes in the physical properties of soil depending on the utilization conditions of the Special Protected National Park compared to the area fenced for more than 10 years. The stability and stabilization of the stabilized mountain meadow soil stabilization and physical properties of soil in the Gorkhi-Terelj National Park (GTNP) resort and limited concentration of tourism. As a result of the study, the stability of the soil structure was 2.8 points in the area of vegetation cover 0-3 cm outside the fence, while the 2.6 layered soil layers above the soils of the vegetation cover. However, the area with vegetation cover within the fence is 4.2 points in soil 0-3 cm and 4 leaves in soil without vegetation cover.

scholarly journals Comparative Study between Silica Fume and Nano Silica Fume in Improving the Shear Strength and Collapsibility of Highly Gypseous Soil

2020 ◽  
Vol 27 (1) ◽  
pp. 72-78
Author(s):  
Ahmed Al-Obaidi ◽  
Marwa Al-Mukhtar ◽  
Omar Al-Dikhil ◽  
Saeed Hannona
Keyword(s):  
Shear Strength ◽  
Silica Fume ◽  
Friction Angle ◽  
Engineering Properties ◽  
Nano Silica ◽  
Direct Shear Tests ◽  
Apparent Cohesion ◽  
Gypsum Content ◽  
Wet Condition ◽  
Gypseous Soil

Soils with highly gypsum content signify known as soils that exhibit collapsibility and sudden failure when being submerged to wetting. Many of the constructions built on this soil showed cracked and/or collapsed at some parts as these soils immersed or leached with water. The utilization of extremely fine materials, for example, Microscale or Nanoscale, is generally utilized these days. This research compared the use of Silica fume (SF) (micro material) and Nano Silica fume (NSF) (Nanomaterial) to explore the capability of these very fine materials to mend the shear strength and collapsibility properties of highly gypseous soils. The soil as Poorly Graded Sand (SP) was used, with a gypsum amount equal to 62%. A succession of direct shear tests and double odometer tests were carried on dry and submarined specimens of soil at various percentages of SF and NSF. The obtained results indicate that mixing the highly gypseous soils with SF or NSF improved the engineering properties of these soils, especially for the wet condition. The average increment in apparent cohesion when adding SF (5-20) percentage varies between (140-310) % in dry soil and (20-40) % in soaked soil. Same results obtained when mixing the gypseous soils with (1-5) % of NSF. Also, the Nanomaterial provided an improvement of the friction angle in dry and submerged cases respectively. Considering that, the SF gives adverse results upon the friction angle of the soil. The SF and the NSF both condensed the dangers of gypseous soil collapsibility. Consequently, the use of NSF can be assertively suggested to improve the engineering characteristics of highly gypseous soils when compared with SF, where only mixing of 3% of NSF gives the best results.

Effect of Cavities from Gypsum Dissolution on Bearing Capacity of Soil under Square Footing

2020 ◽  
Vol 857 ◽  
pp. 221-227
Author(s):  
Israa Saleh Hussein ◽  
Lamyaa Najah Snodi
Keyword(s):  
Bearing Capacity ◽  
Water Flow ◽  
Three Dimensional ◽  
Cavity Volume ◽  
Finite Element Program ◽  
Square Footing ◽  
Gypsum Content ◽  
Element Program ◽  
Three Dimensional Finite Element ◽  
Gypseous Soil

This study deals with cavities under square footing which resulted from gypsum dissolving due to water flow in gypseous soil. This process leads to collapse of soil structure and progressive compression. A model was developed for governing the mass-transport to assess the variation of gypsum content of the soil during dissolution by ground water flow then cavity formation was adopted. A general three-dimensional finite element program (PLAXIS 3D) was selected for numerical analysis method to generate the solution. The study included a number of variables and their effect on bearing capacity of gypseous soil such as (gypsum content, cavity volume and location). The cavity was represented as axis and plane cavity which has square section. The results show that the most dangerous case is found when the cavity locates at the center of footing base (Z/B = 0), where the bearing capacity decreased by (14, 37, and 69%) for (20, 30, and 40%) gypsum dissolving ratio respectively. Also, the bearing capacity decreased when the cavity volume increases due to increasing dissolution ratio. The effect of cavity became disappear after (Z/B = 4). While, when using plane cavity, there was no cavity at center of footing base (Z/B = 0) because it considered as a hole not cavity. When using plane cavity, the bearing capacity decreased by (28, 43, and 53%) for (20, 30, and 40%) dissolving ratio respectively when (Z/B=1). The effect of cavity on the bearing capacity would be disappear as the distance from footing center increase until it became disappear at (Z/B = 6 m). The plane cavity is more dangerous than axis cavity.

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