{"689426":{"#nid":"689426","#data":{"type":"event","title":"PhD Defense by Meron Berhanu Belachew","body":[{"value":"\u003Cp\u003ESchool of Civil and Environmental Engineering\u003C\/p\u003E\u003Cp\u003EPh.D. Thesis Defense Announcement\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EBIO-INSPIRED SOIL EXCAVATION AND PENETRATION: IMAGE-GUIDED NUMERICAL MODELING AND EXPERIMENTAL INVESTIGATIONS\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EBy\u003Cstrong\u003E\u0026nbsp;Meron Berhanu Belachew\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EAdvisors:\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EDr. J. David Frost (GT \u2013 CEE) \u0026amp; Dr. Chlo\u00e9 Arson (Cornell University \u2013 EAS)\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003ECommittee Members:\u003Cstrong\u003E\u0026nbsp;Dr. Sheng Dai (GT \u2013 CEE), Dr. Catherine O\u0027Sullivan (Imperial College London \u2013 CEE), Dr. Gioacchino Viggiani (Universit\u00e9 Grenoble Alpes \u2013 Laboratoire 3SR)\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EDate and Time:\u003Cstrong\u003E\u0026nbsp;April 20, 2026. 7:00AM EST\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003ELocation:\u0026nbsp;SEB122 or\u0026nbsp;\u003Ca href=\u0022https:\/\/gatech.zoom.us\/j\/94160328747\u0022\u003E\u003Cstrong\u003Ehttps:\/\/gatech.zoom.us\/j\/94160328747\u003C\/strong\u003E\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ESubsurface excavation and penetration are central to geotechnical engineering\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eapplications including trenchless technologies, tunneling, site characterization,\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eanchoring, and underground infrastructure installation. Conventional engineering\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eapproaches often rely on tunnels of simple geometries and linear paths, as well as\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Ebrute-force pure soil removal or pure soil displacement. These methods often\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Erequire high energy input and induce significant ground disturbance. In contrast,\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Emany biological systems achieve efficient underground construction and\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Elocomotion through controlled geometry, staged excavation, and adaptive\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Esubsurface advancement combining excavation and penetration. This thesis\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Einvestigates how such natural strategies can inform the analysis and design of bioinspired\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Egeotechnical systems.\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EThe research focuses on three complementary studies. First, the architecture of\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EHarvester ant nests is obtained using three-dimensional scanning of in-situ castings\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eto identify geometric characteristics relevant to underground stability. Shaft Georgia Institute of Technology\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003ESchool of Civil and Environmental Engineering\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EAtlanta, Georgia 30332-0355 U.S.A.\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EPhone: 404.894.9044\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EA Unit of the University System of Georgia \u2022 An Equal Education and Employment Opportunity Institution\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Egeometries, chamber shapes, sizes, and spatial arrangement are examined, and\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Etheir influence on stress redistribution in the surrounding soil is evaluated through\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Enumerical modeling and analytical solutions. The analyses show that ant nest\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Estructures can be reasonably represented using mathematical models that mimic\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Ethe natural systems, and that their geometry and spatial distribution enhance the\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Emechanical stability of the surrounding soil.\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003ESecond, the thesis investigates staged excavation strategies inspired by ant nest\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Econstruction and compares them with conventional single-pass excavation. Finite\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eelement analysis is used to study the effects of excavation sequencing on stress\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eplastic strain development, and energy demand. The results demonstrate that\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Estaged excavation can reduce the mechanical work required relative to single-pass\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eexcavation under comparable conditions, although with slightly higher and more\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Elocalized plastic shear strain.\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EThird, a bio-inspired soil penetration concept motivated by root growth, centipedelike\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Emotion, and vortex geometries is developed and studied. This compound\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Econcept integrates functions observed in biological systems into a solution that lies\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Ebetween pure excavation and pure penetration, with the goal of reducing energy\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Edemand, penetration resistance, and subsurface disturbance. Experimental devices\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eare designed and tested in granular soils, including systems compatible with X-ray\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Ecomputed tomography imaging. Time-lapse photography, digital image correlation,\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EX-ray CT, continuum-based and particle-scale digital volume correlation are used to\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Echaracterize soil deformation at the micro-scale and interpret it alongside macroscale\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Emeasurements of external response measurements and work input. The\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eresults show that the friction-reversal component of the device can generate selfpenetration,\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Ewhile combined linear and rotational motion with vortical tip geometries\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Ecan reduce disturbance, energy demand, and tip penetration resistance, while also\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Eexpanding the information that may be retrieved from in-situ penetration tests.\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EOverall, this thesis demonstrates that biologically inspired excavation and\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Epenetration strategies provide a useful framework for rethinking geotechnical\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Esystems. By combining numerical modeling, experimental mechanics, and imagebased\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Echaracterization, the work establishes links between natural subsurface\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Econstruction and engineering implementation. The findings contribute to both the\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Efundamental understanding of soil-structure interaction and the development of\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Emore efficient, lower-disturbance geotechnical technologies.\u003C\/strong\u003E\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cstrong\u003EBIO-INSPIRED SOIL EXCAVATION AND PENETRATION: IMAGE-GUIDED NUMERICAL MODELING AND EXPERIMENTAL INVESTIGATIONS\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"BIO-INSPIRED SOIL EXCAVATION AND PENETRATION: IMAGE-GUIDED NUMERICAL MODELING AND EXPERIMENTAL INVESTIGATIONS"}],"uid":"27707","created_gmt":"2026-04-02 19:59:28","changed_gmt":"2026-04-02 20:00:21","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2026-04-20T07:00:00-04:00","event_time_end":"2026-04-20T11:00:00-04:00","event_time_end_last":"2026-04-20T11:00:00-04:00","gmt_time_start":"2026-04-20 11:00:00","gmt_time_end":"2026-04-20 15:00:00","gmt_time_end_last":"2026-04-20 15:00:00","rrule":null,"timezone":"America\/New_York"},"location":"SEB122 ","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}