CAREER: Inspiring a New Paradigm in Geotechnical Design and Education Through an Understanding of Biomimetic Load Transfer in Soils

University Of Arkansas, Fayetteville AR

Investigators

Abstract

This Faculty Early Career Development Program (CAREER) grant will support research that will advance the fundamental understanding of how loads are transferred through soils, and how biological mechanisms and new construction techniques can improve the use of soil as a building material. Many natural materials have geometrical microstructures which make them stronger and tougher than their base materials. This research will provide the needed knowledge so that these mechanisms can be incorporated in soils using additive manufacturing (i.e. 3D printing) techniques in which soils are "printed" into structural components or cellular patterns to improve their load carrying ability. Bio-inspired structures like the honeycomb have been studied for metals and other solid materials; however, an understanding of the effectiveness of these load transfer mechanisms in particulate materials like soils is lacking. Improving a soil's ability to carry load will result in more sustainable and cost-effective geotechnical practice by reducing the amounts of concrete and other materials needed for a project. The fundamental understanding gained in this project will also move additive manufacturing further towards becoming a viable option for building shelters and other infrastructure in remote and underdeveloped locations, and in disaster relief or war-torn areas. Additionally, this project seeks to promote interdisciplinary education through a new course and the participation and retention of diverse students through activities such as K-12 outreach focused on exploring engineering principles in nature, visual-spatial workshops, and recruitment of high quality researchers through the University's Engineering Career Awareness Program. Hierarchical microstructures give many natural materials strengths which are orders of magnitude greater than their constituents. The research goal of this CAREER grant is to leverage these biomimicry concepts to advance the fundamental understanding of load transfer mechanisms in soil. While researchers have observed benefits for similar bio-inspired designs of metals and composites, a fundamental understanding of the effectiveness of these load transfer mechanisms in brittle particulate materials like soils is needed. Therefore, this grant focuses on: (1) understanding the optimized load carrying mechanisms in nature and mimicking these mechanisms in soils; (2) evaluating the behaviors of bio-inspired soils across the length scales using experimental testing and discrete element method (DEM) modeling; and, (3) investigating additive manufacturing as a means to construct cellular soil fabrics and infrastructure at the field-scale. In addition to the DEM simulations, a topology-based method for optimizing the patterns for a given loading scenario and capturing the resulting behavior is necessary to provide a solution for the many possible geotechnical applications. Laboratory and mid-scale testing of bio-improved soils will also be conducted to assess the feasibility of full-scale implementation of the process. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.