Saturated–Unsaturated behaviour of compacted clays

Simple item page
dc.contributor.advisorAzam, Shahid
dc.contributor.authorParanthaman, Rajeevkaran
dc.contributor.committeememberHuang, Gordon
dc.contributor.committeememberMuthu, Jacob
dc.contributor.committeememberSalad Hersi, Osman
dc.contributor.externalexaminerMohamedelhassan, Eltayeb Eltahir
dc.date.accessioned2024-09-25T21:46:30Z
dc.date.available2024-09-25T21:46:30Z
dc.date.issued2023-10
dc.descriptionA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Environmental Systems Engineering, University of Regina. xiv, 228 p.
dc.description.abstractClayey soils are often compacted for geotechnical and geo-environmental construction such as hydraulic dams, road embankments, tailings containment facilities, and municipal landfills. Post construction, these earthworks are exposed to variations in seasonal weather and extreme climatic events (drought, flood, and freezing), contaminations (deicing salts, ion-rich slurries, and toxic leachates), and applied stresses (self-weight, vehicular traffic, and heavy equipment), thereby affecting the integrity of civil infrastructures. The geotechnical behavior (flow through, volume change, and shear strength) is governed by soil composition and compaction, soil-water-electrolyte mechanisms, soil-atmosphere interactions, and field conditions. This research focused on developing a clear understanding of saturated–unsaturated behavior of compacted clays. For this purpose, a representative clayey soil possessing a moderate water adsorption capacity (liquid limit of 29% and plastic limit of 15%) was characterized to provide baseline geotechnical properties. This material was classified as lean clay according to the Unified Soil Classification System. Field behavior was simulated using regional climatic conditions and environmental loading along with test results. The compacted clay was found to have an air entry value of 700 kPa and a residual suction value of 5 × 104 kPa along with s-shaped swell-shrink curve for dry of optimum and j-shaped for wet of optimum. At optimum, osmotic suction was operative within the 70-100% saturation range and showed a j-shaped swell-shrink curve for deionized water and a cascading j-shaped curve for concentrated brine. The transient swelling potential exhibited s-shaped curves irrespective of the degree of compaction and the type of pore fluids. Likewise, the hydraulic and thermal properties of the soil were found to be governed by net water flux and air temperature. Based on the coupled hydraulic-thermal model, the active depth of soil was found to be about 4 m for degree of saturation and 3 m for heat flux. Furthermore, slope stability investigations showed that the environmental loading and soil properties were effectively captured but construction practices and site geology were only partly incorporated. The main innovative contributions are the development of the following: (i) simplified approach for volumetric constitutive relationships using soil suction and applied stress through normalized void ratio; (ii) soil-water-electrolyte framework to capture the effect of soil contaminations; (iii) coupled hydraulic-thermal model to predict the soil behavior under extreme climatic conditions; and (iv) systematic design approach for selecting the most stable geometry. The findings and the contributions of this research are useful for better design, effective construction, and long-term performance of earth structures.
dc.description.authorstatusStudenten
dc.description.peerreviewyesen
dc.identifier.urihttps://hdl.handle.net/10294/16393
dc.language.isoenen
dc.publisherFaculty of Graduate Studies and Research, University of Reginaen
dc.titleSaturated–Unsaturated behaviour of compacted clays
dc.typeThesisen
thesis.degree.departmentFaculty of Engineering and Applied Science
thesis.degree.disciplineEngineering - Environmental Systems
thesis.degree.grantorUniversity of Reginaen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophy (PHD)en
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Paranthaman,Rajeevkaran_PhD_ESE_Thesis_2024Spring.pdf
Size:
4.9 MB
Format:
Adobe Portable Document Format
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
2.22 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Doctoral Theses and Dissertations