{"id":{"repo_id":"uwo","oai_identifier":"oai:uwo.scholaris.ca:20.500.14721/38564"},"canonical_url":"https://search.dev.ndltd.org/etd/uwo/oai:uwo.scholaris.ca:20.500.14721/38564","repository":{"repo_id":"uwo","name":"Western University","base_url":"https://uwo.scholaris.ca/server/oai/request"},"display":{"title":"Basal Stability of Braced Circular Excavations in Isotropic and Anisotropic Clays","abstract":"This study provides a comprehensive numerical analysis of the stability of basal heave in braced circular excavations in undrained soft clays. This analysis was conducted using the finite element method, focusing on both isotropic and anisotropic strength conditions. The initial study utilized the classic Mohr-Coulomb elastic-perfectly plastic constitutive model for isotropic, homogeneous strength conditions. This phase investigated the influence of excavation depth-to-width ratio (H/B), wall embedment depth (D), clay thickness (T), and soil-wall interface roughness (Rint) below the excavation. In the next phase of the study, the NGI-ADP anisotropic strength model was utilized. In this set of analyses, the anisotropy ratio (SuP/SuA), strength gradient (kH/Suo), initial mobilization ratio (τ₀/SuA) and Rint were identified as the key factors. Across a broad range of H/B ratios, both analyses show that narrower excavations exhibit superior resistance to basal heave, with failure mechanisms adopting different forms of localization for different conditions. The stability factor Nc was found to vary from 7.15 to 95.88 for the different analyses. Increased wall embedment depth and rougher interfaces provide more stabilizing, constraining failure surfaces, thereby, enhancing the factor of safety. Under anisotropic conditions, lower SuP/SuA ratios are associated with reduced stability, whereas higher kH/Suo ratios are indicative of stiffer profiles, which contribute to improved stability. The integration of these analyses, supported by the observed failure mechanisms and stability charts, elucidate the detailed relationships between the governing parameters and the basal stability. As part of this study, regression-based equations were derived, which can be employed as quick and reliable engineering tools for estimating basal stability.","abstract_html":"This study provides a comprehensive numerical analysis of the stability of basal heave in braced circular excavations in undrained soft clays. This analysis was conducted using the finite element method, focusing on both isotropic and anisotropic strength conditions. The initial study utilized the classic Mohr-Coulomb elastic-perfectly plastic constitutive model for isotropic, homogeneous strength conditions. This phase investigated the influence of excavation depth-to-width ratio (H/B), wall embedment depth (D), clay thickness (T), and soil-wall interface roughness (Rint) below the excavation. In the next phase of the study, the NGI-ADP anisotropic strength model was utilized. In this set of analyses, the anisotropy ratio (SuP/SuA), strength gradient (kH/Suo), initial mobilization ratio (τ₀/SuA) and Rint were identified as the key factors. Across a broad range of H/B ratios, both analyses show that narrower excavations exhibit superior resistance to basal heave, with failure mechanisms adopting different forms of localization for different conditions. The stability factor Nc was found to vary from 7.15 to 95.88 for the different analyses. Increased wall embedment depth and rougher interfaces provide more stabilizing, constraining failure surfaces, thereby, enhancing the factor of safety. Under anisotropic conditions, lower SuP/SuA ratios are associated with reduced stability, whereas higher kH/Suo ratios are indicative of stiffer profiles, which contribute to improved stability. The integration of these analyses, supported by the observed failure mechanisms and stability charts, elucidate the detailed relationships between the governing parameters and the basal stability. As part of this study, regression-based equations were derived, which can be employed as quick and reliable engineering tools for estimating basal stability.","abstract_has_math":false,"creators":["Ara, Sabrin"],"institution":"The University of Western Ontario","degree_name":"M Eng Sci","degree_level":null,"degree_discipline":"Civil and Environmental Engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Newson, Timothy, A."],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-07-22","date_published":"2025-07-22","updated_at":"2026-07-27T21:56:11Z","subjects":["Basal heave stability","Parametric analysis","Stability factor","Finite element method","Shear strength reduction","Regression-based equations."],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/20.500.14721/38564","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Newson, Timothy, A."]},{"key":"dc:creator","label":"Author","values":["Ara, Sabrin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-08-22T15:38:50Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-08-22T15:38:50Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-07-22"]},{"key":"dc:publisher","label":"Institution","values":["The University of Western Ontario"]},{"key":"dc:type","label":"Dc Type","values":["thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Civil and Environmental Engineering"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M Eng Sci"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["The University of Western Ontario"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Basal heave stability","Parametric analysis","Stability factor","Finite element method","Shear strength reduction","Regression-based equations."]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/20.500.14721/38564"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This study provides a comprehensive numerical analysis of the stability of basal heave in braced circular excavations in undrained soft clays. This analysis was conducted using the finite element method, focusing on both isotropic and anisotropic strength conditions. The initial study utilized the classic Mohr-Coulomb elastic-perfectly plastic constitutive model for isotropic, homogeneous strength conditions. This phase investigated the influence of excavation depth-to-width ratio (H/B), wall embedment depth (D), clay thickness (T), and soil-wall interface roughness (Rint) below the excavation. In the next phase of the study, the NGI-ADP anisotropic strength model was utilized. In this set of analyses, the anisotropy ratio (SuP/SuA), strength gradient (kH/Suo), initial mobilization ratio (τ₀/SuA) and Rint were identified as the key factors. Across a broad range of H/B ratios, both analyses show that narrower excavations exhibit superior resistance to basal heave, with failure mechanisms adopting different forms of localization for different conditions. The stability factor Nc was found to vary from 7.15 to 95.88 for the different analyses. Increased wall embedment depth and rougher interfaces provide more stabilizing, constraining failure surfaces, thereby, enhancing the factor of safety. Under anisotropic conditions, lower SuP/SuA ratios are associated with reduced stability, whereas higher kH/Suo ratios are indicative of stiffer profiles, which contribute to improved stability. The integration of these analyses, supported by the observed failure mechanisms and stability charts, elucidate the detailed relationships between the governing parameters and the basal stability. As part of this study, regression-based equations were derived, which can be employed as quick and reliable engineering tools for estimating basal stability."]},{"key":"dc:title","label":"Title","values":["Basal Stability of Braced Circular Excavations in Isotropic and Anisotropic Clays"]}]}],"canonical_facts":{"dc:contributor.advisor":["Newson, Timothy, A."],"dc:creator":["Ara, Sabrin"],"dc:date.accessioned":["2025-08-22T15:38:50Z"],"dc:date.available":["2025-08-22T15:38:50Z"],"dc:date.issued":["2025-07-22"],"dc:description.abstract":["This study provides a comprehensive numerical analysis of the stability of basal heave in braced circular excavations in undrained soft clays. This analysis was conducted using the finite element method, focusing on both isotropic and anisotropic strength conditions. The initial study utilized the classic Mohr-Coulomb elastic-perfectly plastic constitutive model for isotropic, homogeneous strength conditions. This phase investigated the influence of excavation depth-to-width ratio (H/B), wall embedment depth (D), clay thickness (T), and soil-wall interface roughness (Rint) below the excavation. In the next phase of the study, the NGI-ADP anisotropic strength model was utilized. In this set of analyses, the anisotropy ratio (SuP/SuA), strength gradient (kH/Suo), initial mobilization ratio (τ₀/SuA) and Rint were identified as the key factors. Across a broad range of H/B ratios, both analyses show that narrower excavations exhibit superior resistance to basal heave, with failure mechanisms adopting different forms of localization for different conditions. The stability factor Nc was found to vary from 7.15 to 95.88 for the different analyses. Increased wall embedment depth and rougher interfaces provide more stabilizing, constraining failure surfaces, thereby, enhancing the factor of safety. Under anisotropic conditions, lower SuP/SuA ratios are associated with reduced stability, whereas higher kH/Suo ratios are indicative of stiffer profiles, which contribute to improved stability. The integration of these analyses, supported by the observed failure mechanisms and stability charts, elucidate the detailed relationships between the governing parameters and the basal stability. As part of this study, regression-based equations were derived, which can be employed as quick and reliable engineering tools for estimating basal stability."],"dc:identifier.uri":["https://hdl.handle.net/20.500.14721/38564"],"dc:language.iso":["en"],"dc:publisher":["The University of Western Ontario"],"dc:subject":["Basal heave stability","Parametric analysis","Stability factor","Finite element method","Shear strength reduction","Regression-based equations."],"dc:title":["Basal Stability of Braced Circular Excavations in Isotropic and Anisotropic Clays"],"dc:type":["thesis"],"thesis:degree_discipline":["Civil and Environmental Engineering"],"thesis:degree_name":["M Eng Sci"],"thesis:institution_name":["The University of Western Ontario"]},"updated_at":"2026-07-27T21:56:11Z"}