Deployable ground anchors: Analysis for coastal resilience applications

Deployable and compliant structures are of growing interest within structural engineering as they are useful in the development of efficient, compact, transportable, and cost-effective designs. While both deployable and compliant systems undergo shape change, deployable structures use joints to expand from a compacted state, and compliant structures change shape through small deformations. Both deployable and compliant structures have been applied to various engineering applications but have yet to be explored in their use underground. The focus of this study, a ground anchor that employs deployable, compliant attachments, referred to as awns, is an innovative design that improves the performance of typical cylindrical piles. Coastal communities bordering the Great Lakes contend with the persistent challenge of coastal recession, which is attributable to fluctuating lake levels and constant wave action. This degradation, being exacerbated by climate change, is a growing concern as it can affect existing and future structures near shorelines. Cylindrical piles have traditionally been employed to stabilize steep slopes and protect coastlines. However, these systems are not designed for advanced mechanics and generally require a large factor of safety. They are installed with impact or vibration hammers, causing damage to nearby existing structures. Deployable ground anchors employ deployable and compliant awns to increase the surface area interacting with the adjacent soil, making them a more compact, efficient design as opposed to cylindrical piles. Additionally, these ground anchors utilize a torque-driven installation process, similar to that of drilled shafts, which mitigates the induced vibrations in the soil and the chance of damaging neighboring structures. The work in this thesis explores the soil-structure interactions that occur during the deployment of the awn attachments to further the understanding of the application of deployable ground anchors for coastal resilience. Small-scale, prototype tests that employ ink-tracking techniques are performed to analyze the shear plane location that results from the deployment of the awns as well as the optimal spacing range for anchors that deploy adjacently. The findings from these studies are used to test the anchors in grid formations. An algorithm is developed to find equivalent bar-and-hinge models for the awns. Dynamic relaxation is used to calculate soil stiffness values and perform a structural analysis to determine the force distribution within the awn attachments during deployment. These experimental and computational studies will serve as a foundation for future work on deployable ground anchors for coastal protection.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Civil Engineering

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Capretta, Elizabeth P

Contributors dc:contributor

• Sychterz, Ann C

• Deployable structures
• Compliant structures
• Coastal resilience
• Piles
• Shear plane
• Pile spacing
• Dynamic relaxation
• Bar-and-hinge model
• Soil stiffness

Statement dc:rights

• Copyright 2025 Elizabeth P. Capretta

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129608

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129608