Increasing pull-out capacity of granular pile anchors in expansive soils using base geosynthetics

2000 ◽  
Vol 37 (4) ◽  
pp. 870-881 ◽  
Author(s):  
B R. Phani Kumar ◽  
N Ramachandra Rao
Keyword(s):  
Expansive Soils ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Ground Movement ◽  
Anchor Plate ◽  
Pull Out ◽  
Swelling Soil ◽  
Granular Pile ◽  
Load Rate ◽  
Uplift Load

Granular pile anchors are innovative and effective in resisting the uplift pressure exerted on the foundation by a swelling expansive soil. In a granular pile anchor, the foundation is anchored at the bottom of the granular pile to an anchor plate with the help of a mild steel rod. This renders the granular pile tension-resistant and enables it to offer resistance to the uplift force exerted on the foundation by the swelling soil. This resistance to uplift or pull-out load depends mainly upon the shear parameters of the pile-soil interface and the lateral swelling pressure of the soil, which confines the pile radially and prevents it from being uplifted. The resistance to uplift can be increased by placing a base geosynthetic above the anchor plate so that it forms an integral part of the granular pile anchor. The increase in resistance is due to the friction mobilized between the geosynthetic and the confining media when the uplift load acts on the pile and the geosynthetic moves along with the pile. Hence it depends on the friction between the geosynthetic and the confining media and the area and stiffness of the geosynthetic. This paper discusses the effects of these parameters on pull-out load, rate of heave, and relative ground movement near the pile surface.Key words: expansive soil, granular pile anchor, base geosynthetic, ground movement, rate of heave, pull-out load.

scholarly journals Ground improvement using granular pile anchor system: resistance to heave and uplift pressure

2020 ◽  
Vol 19 (1) ◽  
pp. 403
Author(s):  
Alvin John Lim Meng Siang ◽  
Ehab Hamad Sfoog ◽  
Nahla Naji ◽  
Sim Sy Yi ◽  
Nickholas Anting Anak Guntor ◽  
...  
Keyword(s):  
Moisture Absorption ◽  
Expansive Soils ◽  
Ground Improvement ◽  
Reinforced Soil ◽  
Scale Model ◽  
Small Scale ◽  
Numerical Investigations ◽  
Anchor System ◽  
Pull Out ◽  
Granular Pile

<span lang="EN-GB">Expansive soil is found in many parts of the world where its major drawback is its expansion and shrinking property upon moisture absorption and drying during alternation of rainy-dry seasons. Due to its swelling-shrinkage repeated process, fatigue and distress cause crack to structures. Granular pile anchor (GPA) system is a pioneering technique that is utilised in reinforcing these expansive soils. Granular pile anchor (GPA) system is a pioneering technique that is utilised in reinforcing expansive soils. The GPA provides tensile resistance which arrest the exerted upward forces and hence reducing heave. Previous investigations have only focused on load-displacement relationships by utilizing the pull-out technique. In this technique, an external force pulls the GPA and the corresponding displacements are recorded. The results provide indication of the GPA resistance to the applied force. However, in real conditions the heave and expansion forces were developed as a result of the pressure caused by the water absorption which pushes the entire soil bed in the upward direction along with the GPA. Therefore, this paper is aimed to explore this concept by carrying experimental and numerical investigations on a small scale model for a single pile with a diameter of 4 cm, with lengths of 20 and 40 cm. Ultimately, the reinforced soil exhibits reduction in upward force and heave compared to the unreinforced soil. Also, verifications for the testing shows that the relationship between the upward force and heave exhibits almost linear relationship for both experimental and numerical investigations. Therefore, shallow foundations incorporated with a GPA system proves to effectively lessen the heave that occurs in expansive soils which in turn can solve problems for constructions.</span>

scholarly journals An Experimental Study on the Effect of Micro-Metakaolin on the Strength and Swelling Characteristics of Expansive Soils

2022 ◽  
Author(s):  
Mohamed Sakr ◽  
Waseim Azzam ◽  
Mohamed Meguid ◽  
Hebatalla Ghoneim
Keyword(s):  
Expansive Soils ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Soil Conditions ◽  
Arid Areas ◽  
Continuous Increase ◽  
Swell Index ◽  
The World ◽  
Swelling Characteristics ◽  
The Government

Abstract Expansive soils are found in many parts of the world, especially in arid areas and dry weather regions. Urbanization and development of new cities around the world resulted in construction in areas of challenging subsurface soil conditions. For example, in the Middle East, the Government of Egypt is building several new cities to accommodate the continuous increase in the country’s population. Most of these new cities are located in areas underlain by expansive soils. In this study, a series of laboratory tests were carried out to investigate the effect of introducing micro-metakaolin into the matrix of an expansive soil to improve the swelling potential as a new stabilizing material. Test results showed that micro-metakaolin can considerably decrease the free swell index of the soil by 37% and 54% at micro-metakaolin content of 15% and 25%, respectively. In addition, the shear strength of the soil was found to also increase as a result of the introduction of the micro-metakaolin material. Adding 25% micro-metakaolin content reduced the swelling pressure of the soil by about 33%. The results suggest that the proposed method is efficient in stabilizing and improving the properties of expansive soils found in arid areas. This is important to control excessive swelling and prevent possible damage to the supported structures.

scholarly journals Prediction of final settlements of buildings constructed on expansive soils

2015 ◽  
Vol 4 (3) ◽  
pp. 424
Author(s):  
María-de-la-Luz Pérez-Rea ◽  
Tania Ayala ◽  
Victor Castano
Keyword(s):  
Soil Structure ◽  
Expansive Soils ◽  
Volumetric Strain ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Soil Structure Interaction ◽  
Soil Behavior ◽  
Building Conditions ◽  
Structure Interaction ◽  
Strain Coefficient

Because the action of the swelling pressure, the settlements caused by the transmitted load from the structure on expansive soils, and the settlements calculated by classic theories of soils mechanics are different. This swelling pressure acts in opposite direction to the weight of the building. In this paper, the authors propose the use of a volumetric strain coefficient by settlements exp, in a soil-structure interaction algorithm taking into account the expansive soil behavior in the reduction of the settlement magnitude when a building is placed above soil. It’s necessary to know the initial properties of the expansive unsaturated soil and the load building conditions. A laboratory process is described for determining the aexpcoefficient.

Model for the simulation of swelling-pressure measurements on expansive soils

1998 ◽  
Vol 35 (1) ◽  
pp. 96-114 ◽  
Author(s):  
Fangsheng Shuai ◽  
D G Fredlund
Keyword(s):  
Pore Water ◽  
Volume Change ◽  
Unsaturated Soil ◽  
Pore Water Pressure ◽  
Expansive Soils ◽  
Water Pressure ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Oedometer Test ◽  
Free Swell

Numerous laboratory swelling tests have been reported for the measurement of swelling pressure and the amount of swell of an expansive soil. These test methods generally involve the use of a conventional one-dimensional oedometer apparatus. Few attempts, however, have been made to formulate a theoretical framework to simulate the testing procedures or to visualize the different stress paths followed when using the various methods. The simulation of the oedometer tests on expansive soils is required to fully understand the prediction of heave. The correct measurement of swelling pressure is required for an accurate prediction of heave. It is further anticipated that some information on unsaturated soils property functions may be approximated from the back-analysis of the data. A theoretical model is proposed to describe the pore-water pressures with time and depth in a specimen as well as the volume changes during various oedometer swell tests. The model is formulated based on equilibrium considerations, constitutive equations for an unsaturated soil, and the continuity requirement for the pore fluid phases. The transient water flow process is coupled with the soil volume change process. The model can be used to describe the volume-change behaviour, pore-water pressure, and vertical total stress development in an unsaturated soil during an oedometer test performed by any one of several test procedures. The model has been put into a finite element formulation using the Galerkin technique. All the parameters required to run the model can be obtained by performing independent, common laboratory tests. The proposed model was used to simulate the results from free-swell, constant-volume, constant water content, and loaded-swell oedometer tests. Computed values of volume change, vertical total stress, and pore-water pressure are in good agreement with measured values.Key words: unsaturated soil, expansive soil, swelling pressure, theoretical simulation, constant-volume oedometer test, free-swell oedometer test, loaded-swell oedometer test.

scholarly journals Factors affecting the swelling pressure for Jerash expansive soil

2021 ◽  
Vol 3 (2) ◽  
pp. 44-51
Author(s):  
Talal Masoud ◽  
Abdulrazzaq Jawish Alkherret
Keyword(s):  
Water Content ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Dry Density ◽  
Initial Water Content ◽  
Content Increase ◽  
Initial Water ◽  
Factors Affecting ◽  
Water Content Increase

  In this study for factors effecting the swelling pressure of jerash expansive soils were investigated in this study, effect of initial dry density and effect of initial water content on the jerash expansive soil were investigated.It show that as the initial dry density decrease from 1.85 gm/cm3  to1.25 gm/cm3 , the swelling pressure also decrease are from 3.1  to 0.25gm/cm2   also it show that as the initial water content increase from 0%to 15% , the swelling pressure of jerash expansive soil decrease from 2.65 gm/cm2  to 1.35 gm/cm2  .  

scholarly journals A Framework for Interpreting Lateral Swelling Pressure in Unsaturated Expansive Soils

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Mingyu Li ◽  
Yanqing Wei ◽  
Yunlong Liu ◽  
Junwei Jin
Keyword(s):  
Expansive Soils ◽  
Soil Mechanics ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Field Studies ◽  
Theoretical Framework ◽  
Water Infiltration ◽  
Civil Infrastructure ◽  
Unsaturated Soil Mechanics ◽  
Unsaturated Expansive Soils

Lateral swelling pressure (LSP) develops when expansive soil volume increment associated with water infiltration is restrained in a confined domain, for example, due to construction of civil infrastructure. In this paper, initially a flowchart is developed to highlight various key factors that influence the LSP mobilization according to lab and field studies collected from previous literature studies. Then extending unsaturated soil mechanics, a theoretical framework is proposed for illustrating the LSP mobilization in the field against retaining structures and pile foundations under different boundary conditions, respectively. An example problem for a basement wall and a pile foundation constructed in a typical expansive soil from Regina, Canada, is presented to illustrate the proposed theoretical framework. The framework and corresponding analysis presented in this paper can facilitate to provide rational designs of geotechnical infrastructures in expansive soils.

Effect of the Grain Size of Sand on Expansive Soil

2020 ◽  
Vol 857 ◽  
pp. 367-373
Author(s):  
Yahya K. Atemimi
Keyword(s):  
Expansive Soils ◽  
Soil Mechanics ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Liquid Limit ◽  
Dry Density ◽  
Sieve Analysis ◽  
Maximum Dry Density ◽  
Sand Mixture ◽  
New Phase

The interest in expansive soils goes as far as they were considered as a new phase of soil mechanics. Problems associated with potential volume change of soils occur worldwide, mainly in the arid and semi-arid climatic region, as is the case of the country of this research. These problems are particularly existed in regions where the variation in the moisture content can cause a potential expansiveness of the soil. In fact, Bentonite/Sand mixture represents one of the available answers for the geotechnical engineering problems such as heaves, cracks and other damages caused by swelling and shrinkage. This mixture may be used to 1) reduce the settlement time of structures, and 2) increase the permeability of soils. The main target of the present work is to demonstrate the influence of adding sand on an expansive soil (bentonite) behavior. This includes an investigation to the effect of the amount and the particles size of sand on the physical properties of the expansive soil. The reduction in swelling and swelling pressure of the expansive soil by the addition of different percentages and different particles size of sand and the consequent effect on strength characteristic were also studied. Thirteen samples of Bentonite/sand mixture were used in this study to evaluate the effect of the sand percentages on the swelling behavior. To implement the laboratory program, many tests were used which were sieve analysis, Atterberg’s limits, compaction, and free swelling test with swelling pressure test. The results indicated a reduction in the liquid limit of around 55% and in the plastic limit of around 54%, where the increase in the maximum dry density was 46%. On the other hand, the reduction in the swelling pressure was 87.5%.

scholarly journals Improvement of the Geotechnical Properties of Expansive Soils Using Fly Ash

2021 ◽  
Vol 56 (1) ◽  
Author(s):  
Nahla M. Salim
Keyword(s):  
Fly Ash ◽  
Specific Gravity ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Geotechnical Properties ◽  
Plasticity Index ◽  
Dry Density ◽  
The Impact ◽  
Swell Pressure

This test program studies the impact of using fly ash on prepared soil by adding different percentages of fly ash (5%, 10% and 15%) by dry soil weight. The expansive soil was prepared in the laboratory by mixing natural soil (Al-Nahrawan clayey soil) with different percentages of bentonite (30%, 50% and 70%). The experimental study focuses on the effects of the fly ash content on the free swell index, swell potential, swelling pressure, plasticity and compaction characteristics of expansive soil. The influence of these admixtures was compared with those of untreated soils. The results show that the plasticity index, the optimum moisture content, swelling percent and swell pressure increase with an increase in the bentonite percentage, and the maximum dry density and specific gravity decrease with increases in the bentonite percentage. The plasticity index, specific gravity, swelling and swelling pressure decrease with increases in the fly ash percentage. The optimum percentage of fly ash was 5%, where the swell and swell pressure decreased by a large amount. The results showed that the addition of fly ash to expansive soils has a positive effect on the soil's geotechnical properties.

scholarly journals Correlation between Swelling Pressure and Free Swell of Greater Cairo City Expansive Soils – A Case Study

2019 ◽  
pp. 1-6
Author(s):  
Nasser A. A. Radwan ◽  
Khaled M. M. Bahloul
Keyword(s):  
Expansive Soils ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Plasticity Index ◽  
Greater Cairo ◽  
Multiple Variable ◽  
Free Swell ◽  
Multiple Variable Regression ◽  
The Relationship

The aim of this research is to investigate experimentally the relationship between free swell, plasticity index of expansive soil found in greater Cairo City Suburbs, Egypt with swelling pressure of mentioned soil. Predicting Swelling Pressure of any soil is a time consuming and expensive test in comparison to determining plasticity index and free swell which are simple, fast and economic tests. In present research six samples of expansive soil were collected from different locations of study area. The method uses single variable and multiple variable regression analysis using Microsoft excel software.

Foundation Failures Mitigation under Expansive Clay by Using Granular Pile Anchor System

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
Ehab Hamad Sfoog ◽  
◽  
Alvin John Lim Meng Siang ◽  
Nahla Naji ◽  
Sim Sy Yi ◽  
...  
Keyword(s):  
New Technologies ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Cost Effective ◽  
Scale Model ◽  
Expansive Clay ◽  
Uplift Capacity ◽  
Anchor System ◽  
Granular Pile ◽  
Stable Zone

Expansive soils are found in typical areas in the world especially in arid and semi-arid regions. The problems associated with this type of soil drive geotechnical engineers to invent new technologies as remediation’s such as physical and chemical treatments. Innovative foundation techniques were also suggested for remedying the swell-shrink problems of the expansive soil. The granular pile anchor (GPA) is relatively a more favorable technique indebted to its cost-effective, easy and fast to assemble and most importantly was found to be more efficient in remedying the expansive soil. Despite the extensive studies on the expansive soil remedies, yet the granular pile anchor system requires more comprehensive and in-depth investigations. This study is aimed at developing a model with granular piles of various length and diameter extended to the stable zone to investigate the heave and uplift pressure in the expansive soil. For this purpose, experimental and numerical analysis were conducted in a small and in a full scale model respectively. A significant improvement was attained in heave reduction and an increment of uplift capacity. The findings also show that heave decreased significantly when the length and diameter of the GPA increases while the uplift capacity increased. However, it was noted that the extension of length to the stable zone resulted in insignificant changes. Therefore, it can be concluded that the maximum length of 6 m is the ideal length for GPA with different diameters according to foundations design requirement for this particular type of soil.

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