Effect of Induced Osmotic Suction on Swell and Hydraulic Conductivity of an Expansive Soil

2018 ◽  
pp. 193-200
Author(s):  
M. Julina ◽  
T. Thyagaraj
Keyword(s):  
Hydraulic Conductivity ◽  
Expansive Soil ◽  
Osmotic Suction

Compressibility and hydraulic conductivity of a chemically treated expansive clay

2001 ◽  
Vol 38 (1) ◽  
pp. 154-160 ◽  
Author(s):  
Zalihe Nalbantoglu ◽  
Erdil Riza Tuncer
Keyword(s):  
Fly Ash ◽  
Hydraulic Conductivity ◽  
Expansive Soil ◽  
Dry Weight ◽  
Pozzolanic Reaction ◽  
Exchange Capacity ◽  
Expansive Clay ◽  
Preconsolidation Pressure ◽  
Few Data ◽  
Published Research

The paper presents a series of laboratory tests and evaluates the effect of lime and fly ash on the compressibility and hydraulic characteristics of an expansive soil in Cyprus. The tests were performed at different percentages of lime (0–7%) and fly ash (15 and 25%) by dry weight of soil, and additional tests were also performed on soils treated with 15% fly ash plus 3% lime. Previously published research reveals that few data are available concerning the compressibility and hydraulic conductivity of lime-treated soils. The results of this study indicate an increase in the vertical effective yield stress (apparent preconsolidation pressure) and a decrease in the compressibility characteristics of the treated soils. Moreover, unlike some of the findings in the literature, higher hydraulic conductivity values were obtained with time. This finding has been substantiated by the reduced cation exchange capacity (CEC) values, which indicate that the pozzolanic reaction causes the soils to become more granular in nature, resulting in higher hydraulic conductivity.Key words: cementation, compressibility, fly ash, hydraulic conductivity, lime.

scholarly journals CLAYEY SOIL AMENDMENT BY HYDROPHILIC NANO BENTONITE FOR LANDFILL COVER BARRIER: A CASE STUDY

2020 ◽  
Vol 28 (3) ◽  
pp. 148-156
Author(s):  
Ahmad Qasaimeh ◽  
Abdulla A. Sharo ◽  
Khalid Bani-Melhem
Keyword(s):  
Hydraulic Conductivity ◽  
Clayey Soil ◽  
Transport Coefficients ◽  
Expansive Soil ◽  
Gas Diffusion ◽  
Soil Samples ◽  
Design System ◽  
Clay Material ◽  
Landfill Cover ◽  
Nano Clay

Methane and carbon dioxide are of major concern as greenhouse gases; the landfills have the problem of controlling these gases. Al Akaider in Jordan is the second biggest landfill suffers controlling gases as it lacks a cover design system. In this work, the main goal is to investigate the appropriateness of amended expansive clayey soil in Irbid as a cover barrier. The expansive soil is unwanted in construction projects, thus the modification of this expelled soil enables using it as a low cost landfill cover barrier. In this research, the effect of adding nano-clay material (Hydrophilic Nano Bentonite) on the geotechnical characteristics, hydraulic conductivity, and gas transport coefficients of the clayey soil are studied. The soil samples were obtained from Irbid city. Unconfined compressive strength and free swelling tests were performed on soil samples with different percentages of nano-clay added in the range (0.1% to 1.2%) by weight. The results indicated that the addition of nano-clay at low percentages increases the strength of expansive soil up to 315 kPa at 0.6% of nano-clay and the swelling potential decreased dramatically with the addition of nano-clay. The optimal percent of nano-clay was found to be 0.6%. The intrinsic permeability of the amended soil was 6.03×10–15 m2. The average values of fluid transport coefficients were determined at 25 °C. The hydraulic conductivity for water was about 6.5×10–10 m/s. Gas conductivity coefficients for CO2 and CH4 were 5×10–9 m/s and 2.5×10–9 m/s respectively. Gas diffusion coefficients for CO2 and CH4 were 3×10–6 m2/s and 4×10–6 m2/s respectively.

scholarly journals Modification of Mechanical Properties of Expansive Soil from North China by Using Rice Husk Ash

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2789
Author(s):  
Mazahir M. M. Taha ◽  
Cheng-Pei Feng ◽  
Sara H. S. Ahmed
Keyword(s):  
Hydraulic Conductivity ◽  
Rice Husk ◽  
North China ◽  
Void Ratio ◽  
Rice Husk Ash ◽  
Clay Soil ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Coefficient Of Consolidation ◽  
Consolidation Coefficient

The construction of buildings on expansive soils poses considerable risk of damage or collapse due to soil shrinkage or swelling made likely by the remarkable degree compressibility and weak shear resistance of such soils. In this research, rice husk ash (RHA) was added to expansive soil samples in different quantities of 0%, 4%, 8%, 12%, and 16% by weight of soil to determine their effects on the plasticity index, compaction parameters, consolidation performance, and California bearing ratio (CBR)of clay soil. The results show that the use of RHA increases the effective stress and decreases the void ratio and coefficient of consolidation. Adding 16% RHA resulted in the greatest reduction in the hydraulic conductivity, void ratio, and coefficient of consolidation. The void ratio decreased from 0.96 to 0.93, consolidation coefficient decreased from 2.52 to 2.33 cm2/s, and hydraulic conductivity decreased from 1.12 to 0.80 cm/s. The addition of RHA improved the soil properties and coefficient of consolidation due to the high density and cohesiveness of RHA. The results of this study can be used to provide a suitable basis for the treatment of expansive soil to provide improved conditions for infrastructure construction.

scholarly journals The Compressibility and Swell of Mixtures for Sand-Clay Liners

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Muawia A. Dafalla
Keyword(s):  
Hydraulic Conductivity ◽  
Expansive Soil ◽  
Clay Content ◽  
Swelling Pressure ◽  
Partial Replacement ◽  
Expansive Clay ◽  
Clay Liners ◽  
Swelling Properties ◽  
Prime Concern ◽  
Swell Percent

Sand-clay liners utilize expansive clay to act as a filler to occupy the voids in the sand and thus reduce the hydraulic conductivity of the mixture. The hydraulic conductivity and transfer of water and other substances through sand-clay mixtures are of prime concern in the design of liners and hydraulic barriers. Many successful research studies have been undertaken to achieve appropriate mixtures that satisfy hydraulic conductivity requirements. This study investigates compressibility and swelling properties of mixtures to ensure that they were acceptable for light structures, roads, and slabs on grade. A range of sand-expansive clay mixtures were investigated for swell and compression properties. The swelling and compressibility indices were found to increase with increasing clay content. The use of highly expansive material can result in large volume changes due to swell and shrinkage. The inclusion of less expansive soil material as partial replacement of bentonite by one-third to two-thirds is found to reduce the compressibility by 60% to 70% for 10% and 15% clay content, respectively. The swelling pressure and swell percent were also found significantly reduced. Adding less expansive natural clay to bentonite can produce liners that are still sufficiently impervious and at the same time less problematic.

Hydraulic conductivity behaviour of expansive soil geopolymer binders

2021 ◽  
Vol 14 (6) ◽  
Author(s):  
Michael E. Onyia ◽  
Jonah C. Agunwamba ◽  
Donald C. Nwonu
Keyword(s):  
Hydraulic Conductivity ◽  
Expansive Soil ◽  
Conductivity Behaviour

scholarly journals Effect of zeolite utilization on volume change and strength properties of expansive soil as landfill barrier

2017 ◽  
Vol 54 (9) ◽  
pp. 1320-1330 ◽  
Author(s):  
Şerife Öncü ◽  
Huriye Bilsel
Keyword(s):  
Hydraulic Conductivity ◽  
Volume Change ◽  
Expansive Soil ◽  
Confining Pressure ◽  
Good Alternative ◽  
Strength Properties ◽  
Landfill Liner ◽  
Swell Potential ◽  
Compressibility Characteristics ◽  
Natural Reserves

A sand–Na–bentonite mixture is widely used as engineering barrier material, which usually possesses hydraulic conductivity below the regulatory limit (10−7 cm/s). However, in some areas natural Na–bentonite is not readily available; instead, an abundantly prevailing local expansive soil can be an alternative. This study assesses the suitability of a local expansive soil mixed with zeolite, easily obtained from natural reserves in Turkey, proposed to be used as a landfill liner in a semi-arid climate. The choice of zeolite is due to its already well-understood high adsorption capacity for heavy metals as well as its pozzolanicity. The volume change, strength, and hydraulic conductivity characteristics were studied with respect to durability through ageing. When an expansive soil to zeolite ratio of 0.5 was used, the results indicated improved properties with curing. Swell potential was observed to decrease by 85% within a 90 day curing period, while a 30%–34% reduction was noted in shrinkage and compressibility characteristics. The hydraulic conductivity was observed to remain below the regulatory limit under all confining pressure ranges studied, provided the curing time was at least 90 days. Moreover, the mixture attained improved strength characteristics with time, and proved to be sustainable over the period studied. Therefore, it was concluded that expansive soil mixed with zeolite could be a good alternative to sand–Na-bentonite, mainly in developing areas of growing population and environmental degradation.

Expansive soil-biochar-root-water-bacteria interaction: Investigation on crack development, water management and plant growth in green infrastructure

2020 ◽  
pp. 105678952097441
Author(s):  
Hao Wang ◽  
Kexin Zhang ◽  
Lin Gan ◽  
Jiaqin Liu ◽  
Guoxiong Mei
Keyword(s):  
Hydraulic Conductivity ◽  
Plant Growth ◽  
Water Content ◽  
Hydraulic Properties ◽  
Biological Effects ◽  
Expansive Soil ◽  
Crack Development ◽  
Dry Density ◽  
Residual Water ◽  
Biochar Amendment

The objectives of the study are to explore fundamental mechanism of expansive soil-biochar-root-water-bacteria interaction, and investigate crack development and hydraulic properties of biochar amended soils aiming at green infrastructures. The physical, chemical and biological effects of biochar on expansive soil have been comprehensively explored. Crack development is investigated quantificationally, and mechanism of soil damage evolution is briefly discussed base on micro-chemical analyses. During outdoor vegetation period, photosynthesis light response curves were measured to evaluate plant growth. After period of vegetation, hydraulic properties of root-soil composites and unplanted soils were compared. The study reveals that soil crack intensity factor decreases by 33.5%, 48.5% and 47.3% due to 5%, 10% and 15% biochar introduction respectively after 5 wetting-drying cycles. 15% biochar amendment helps to restrain both initiation and propagation of soil cracks. Biochar amendment of up to 5% contributes well to residual water content and plant growth (i.e., light saturation point and light compensation point). Excessive biochar addition would restrain roots elongation, and increase saturated water content. Spatial root distribution is changed due to biochar addition, which further influences hydraulic properties and crack development. Hydraulic conductivity and soil dry density share negative correlations, 5% biochar enhances hydraulic conductivity remarkably at relatively loose condition. Biochar amendment also contributes to preventing nitrogen loss and forming more complex bacterial community in soils. The study adds to our knowledge of physio-chemical interactions of biochar with expansive clay, vegetation, water and microorganism.

Unsaturated Hydraulic Conductivity Variation of Expansive Yazoo Clay with Wet-Dry Cycles

2021 ◽  
pp. 036119812110119
Author(s):  
John Ivoke ◽  
Mohammad Sadik Khan ◽  
Masoud Nobahar
Keyword(s):  
Hydraulic Conductivity ◽  
Moisture Content ◽  
Slope Failure ◽  
Expansive Soils ◽  
Initial Moisture Content ◽  
Expansive Soil ◽  
Plastic Clay ◽  
Shrinkage Cracks ◽  
Moisture Variation ◽  
Vertical Hydraulic Conductivity

Expansive soils are subjected to shrink-swell behavior with moisture variation in Mississippi, United States. With successive moisture and temperature variations over the seasons, the hydraulic conductivity of expansive soil is subjected to change because of the development of shrinkage cracks, which can be as large as as 1.2 cm wide and 1.5 m deep in the field, affecting the vertical hydraulic conductivity (Kv), whereas the horizontal hydraulic conductivity (Kh) remains fairly constant. The current study intends to investigate the hydraulic conductivity of highly expansive Yazoo clay at different wet-dry cycles. To observe the changes in the hydraulic conductivity with different wet-dry cycles in the laboratory, an instantaneous profile method to measure the permeability was utilized. Compacted Yazoo clay samples at different initial moisture content instrumented with moisture sensors at different depths to monitor changes in the moisture content were investigated. The samples were subjected to one, two, and three numbers (1N, 2N, and 3N) of wetting and drying cycles. For the drying process, testing chambers are kept in a controlled high-temperature booth of about 37°C simulating high summer temperatures in Mississippi. After the end of the wet-dry cycles, the test is performed to investigate the changes in the hydraulic conductivity of soil with the presence of shrinkage cracks. The hydraulic conductivity of highly plastic clay is very low at a fully compacted state and was observed to be (1.0×10-8 cm/s) at the 1N wetting phase. However, with an increment in the wet-dry cycles, the Kv of Yazoo clay increases (3.70×10-4 cm/s) after the sample is exposed to three wet-dry cycles. Even though the changes in the Kv of highly plastic clay define the infiltration behavior, which mostly controls the slope failure and pavement distress, consideration of the climatic loads is ignored in the design phase of the highway embankment and levees. By inclusion of the climatic variation, and evaluating the performance, the design life and resilience of the structures can be significantly increased

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