Center for Bio-mediated and Bio-inspired Geotechnics
Through 3.8 billion years of trial and error (sometimes referred to as evolution), nature has developed many elegant, efficient, and sustainable biologically based solutions to some of the challenges that vex geotechnical infrastructure systems today. Examples include ant excavation processes that are 1,000 times more energy efficient than man-made tunneling machines, carbonate-cemented sand that is exceptionally resistant to erosion and earthquakes, and self-sensing and self-healing tree root structures that are 10 times more efficient than any mechanical soil reinforcing system developed by humans.
The Center for Bio-mediated and Bio-inspired Geotechnics (CBBG) seeks to understand and harness the scientific processes and principles of natural phenomena such as those cited above to develop more sustainable, safer, less intrusive, more resilient civil infrastructure systems. The Center’s approach embodies a transformational shift from traditional energy-intensive, mechanical methods for engineering the ground to a sustainable, nature-compatible biogeotechnical approach that employs innovative bio-mediated and bio-inspired technologies to meet the demands of modern society.
In the CBBG, Arizona State University (ASU), Georgia Institute of Technology (GaTech), New Mexico State University (NMSU), and the University of California, Davis (UCD) have joined to develop a new generation of geotechnical processes and solutions inspired by nature to transform the design, construction, operation, and maintenance of resilient and sustainable systems for civil infrastructure. The CBBG will realize this vision by combining fundamental scientific research with application-based engineering advances, facilitated by enabling technology and systems integration test beds. CBBG research, development, and implementation will be informed by input from our industry partners to develop sustainable and cost-effective processes and products that can be readily commercialized and deployed in civil infrastructure systems. These partnerships poise the Center to address the pressing need for sustainable infrastructure development to maintain the quality of living in the U.S. and meet the needs of the world’s growing industrialized population.
The CBBG strives to catalyze this transformational shift in engineering practice for geotechnical aspects of infrastructure systems by filling critical gaps in research, education, and workforce development. Many of the problems and opportunities in this emerging field of biogeotechnical engineering are inherently interdisciplinary. The CBBG partners together provide the critical mass needed to integrate the necessary disciplines, bridge knowledge gaps, accelerate technology development, and educate a new generation of engineers, collectively transforming biogeotechnical engineering from a specialty research niche into established practice.
The CBBG integrates research and education programs in biogeotechnical engineering at four Universities into a unified team that addresses the broad spectrum of bio-mediated and bio-inspired geotechnics. The synergy generated by merging these four academic programs into a multi-disciplinary team within a Center that is informed by a robust and diverse Industrial Affiliates program and facilitated by a stable source of long-term funding is accelerating the development and deployment of innovative and transformative biogeotechnical methods in engineering practice.
THRUST 1
HAZARD MITIGATION
The suite of projects in the Hazard Mitigation thrust include systems integration projects on biofilms for seepage control beneath dams and levees, Targeted Bioremediation for Foundations, and Liquefaction Mitigation via MICP and enabling technology projects on Root-Inspired Reinforcement and development of Biostimulation Techniques for Biocementation and Biofilm Development. Biofilms for Seepage Control relies upon the preferred seepage pathway to distribute the necessary microbes and nutrients to the target locations to stimulate biofilm growth for seepage reduction; this technology is applicable to seepage control for dams, levees, and excavations.
Bioremediation for foundations will employ MICP to strengthen and stiffen foundation soil vulnerable to settlement, bearing failure, and lateral displacement/rocking. Root-inspired reinforcement will investigate methods for mimicking the behavior of tree roots to stabilize slopes and enhance foundation performance, laying the groundwork to move toward more efficient “pile-root” topologies for deep foundations and soil reinforcement systems.
Biostimulation for biocementation and biofilm development will advance current UCD studies focused on stimulating indigenous bacteria rather than supplying exogenous bacteria for MICP and biofilm development. Using biostimulation instead of bioaugmentation should ease regulatory and public resistance, reduce cost, and increase treatment uniformity. Related projects under the Environmental Protection and Ecological Restoration thrust include bio-inspired chaotic cyclic push-pull injection schemes and electro-kinetic subsurface transport. The use of synthetic polymers to create 2D and 3D frameworks for structuring mineral precipitation (a cross-cutting project) is another related enabling technology applicable to this thrust.
THRUST 2
ENVIRONMENTAL PROTECTION AND RESTORATION
Projects in the Environmental Protection and Ecological Restoration thrust include the systems integration projects Restoring the Surface Erosion Resistance of Disturbed Soil Sites (via organic matter decomposition and stabilized soil aggregates), Development of a Doubly Cyclic Push-Pull Scheme, the development of Microbially Enhanced Permeable Reactive Barriers, and Restoring the Microbial Crust (in desert soils). Enabling technology projects under this thrust include Electro-Kinetic Subsurface Transport for Mineral Precipitation, and Design and Construction of a Rainfall Simulator. The development of a Doubly Cyclic Push-Pull Scheme seeks to enhance uniform delivery of microbes and nutrients in the subsurface, overcoming geologic heterogeneity. Electro-kinetics employ coupled flows of ions and fluids subject to an electrical potential field to facilitate subsurface transport, even in soils with low hydraulic conductivity. Electro-kinetics can also raise the pH of the pore water, thereby facilitating precipitation. The Permeable Reactive Barrier project will examine the potential for microbially enhancing zeolites to more efficiently remove arsenic and selenium oxyanions from groundwater.
Projects under other thrusts that are related to this thrust include: Biostimulation for Biocementation and Biofilm Development (biostimulation has environmental applications), Engineering Applications of EICP (carbonate precipitation can be used for erosion control and to sequester radionuclides migrating in groundwater), and Carbon Cycle Restoration in Mine Tailings (an ecological restoration technique).
THRUST 3
INFRASTRUCTURE CONSTRUCTION
Systems Integration projects under the Infrastructure Construction thrust include Development of Indigenous Building Materials and Engineering Applications of EICP. Enabling technology projects under this thrust include Development of Bio-inspired Sensors and Sensor Deployment Methods, Development of Adaptive Self-sensing Foundations, and Vibration-induced Self Healing. Development of Bio-inspired Sensors and Sensor Deployment Methods seeks to understand and mimic the sensing systems and borrowing strategies of lizards, moles, mollusks, and worms. Development of Adaptive Self-sensing Foundations seeks to mimic root growth and adaptation to changing boundary conditions. Inspired by bone growth and ant bridges, Vibration-induced Self Healing will explore energy/mass transfer under alternating excitation.
THRUST 4
SUBSURFACE EXPLORATION AND EXCAVATION
Subsurface Exploration and Excavation Projects encourage and foster an inherent synergy within Center activities. An initial suite of projects has been identified that contribute to the systems engineering and translational aspects of Center research. These projects include development of a simulator for coupled bio-thermo-hydro-chemical-mechanical processes and a tool for life cycle sustainability assessment of biogeotechnical systems; a laboratory for bio-memetic studies; and development of bio-inspired sensors. Ongoing Center review and evaluation will lead to additional projects over the life of the Center.
TESTBEDS
The Center will employ a broad array of enabling and systems integration testbeds. Full-scale field testbeds at sites provided by our Industrial Partners will include unpaved roads, landfills, mine tailings, embankments, disturbed and denuded wildfire sites, and a port backlands site. Enabling testbeds include benchtop columns and loading systems in the laboratories of the partner Universities and two major field station sites: the UCD Center for Geotechnical Modeling (CGM) and the ASU East Campus Field Site (ECFS).
The CGM is an existing facility and includes the UCD geotechnical centrifuge (a NEES shared-use facility) and a large soil test pit. The ECFS will be constructed on a 1-acre site on ASU’s East Campus. The ECFS will include the microbial nursery, the rainfall simulator, and a large soil test pit. Equipment available at the facility will include a central data question system, a soils laboratory for index and classification tests, and high-resolution terrestrial Lidar equipment capable of monitoring soil loss due to wind and water erosion with centimeter-level and possibly sub-centimeter precision.
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CBBG brings together a suite of institutions, laboratory facilities and test beds that is unique in the nation, providing exceptional capabilities in leading edge technology and experimental methods. While our facilities are geographically dispersed, we view this as an opportunity to reach a wider student and stakeholder constituency. The CBBG Center is designed to connect its members seamlessly through a shared use policy, and frequent in person and mediated communication.
CBBG is headquartered in the renovated first floor of the Barry M. Goldwater Center for Science and Engineering Building at ASU. Headquartered space includes an Exploration and Training Room fully mediated for distance learning, a state-of-the-art Conference Room, and a Learning and Discovery Center for outreach activities. Facilities at ASU include an approximately 1800 square foot newly renovated wet lab dedicated to biogeotechnics and shared use of three other geotechnical laboratories and the environmental laboratories of the SWETTE Center of Environmental Microbiology (the geotechnical teaching laboratory). CBBG facilities also include a field station on the Polytechnic campus with an ASTM-compliant large scale (40 ft x 8 ft deep rainfall simulator, a geotechnical test pit with a 20ft x 8 ft x 12 ft deep main chamber), and a mobile microbial crust laboratory.
CBBG facilities at the University of California, Davis include the 2,500 square foot Soil Interaction Laboratory equipped with high-end laboratory equipment for biogeotechnics, including incubators, centrifuges, peristaltic pumps, an optical density analyzer, and digital meters for monitoring various chemical compounds. The Center for Geotechnical Modeling at UC Davis is home to a 9 m radius centrifuge affiliated with the NSF National Hazards Engineering Research Infrastructure (NHERI) program and a smaller 1 m radius centrifuge. The large centrifuge can accommodate payloads up to 2000 kg and can model the performance of geo-structural systems subjected to earthquake loading.
Georgia Tech facilities include two unique biogeotechnical testing facilities. The 2,500-square foot Laboratory for Bio-inspired Processes explores biological systems as engineering analogs (e.g., root and reinforcement mechanisms) to identify next-generation bio-inspired processes. The lab is equipped with instrumentation and devices to visualize/monitor biological processes in their natural subsurface environment. The 3,000-square foot High-Pressure Bio-Mediated Processes Laboratory (HPBPL) will allow the study of bio-mediated processes in sediment and jointed rock systems subject to high fluid pressure and effective stress. This HPBPL enables exploratory studies for novel anaerobic consortia from the sea floor and, deep terrestrial environments.
Facilities at New Mexico State University include the Structural Systems and Materials Testing Laboratory, a 2700 square foot facility with a 600 square foot strong floor, providing adequate space for large and small scale subassembly testing. The laboratory is equipped with several high-speed, multi-channel data acquisition systems that allow near simultaneous recording of over 50 channels of data that can be used in the laboratory or transported for site investigations. Additional equipment includes a freeze-thaw chamber, a universal testing machine with 400,000-lb force capacity, and a one million pound compression machine.
FIELD SITES & OTHER EQUIPMENT
Centrifuge and Test Pit (UCD)
High Pressure Bio-Mediated Process Laboratory (GT)
Center for Biologically Inspired Design (GT)
Polytechnic Field Station (ASU)
Structural Testing Facility (NMSU)
Wind Tunnel (ASU/NASA)
Bench-scale testing across all four universities
Arizona State University
Georgia Institute of Technology
New Mexico State University
University of California - Davis
Notice: Please contact international@erc-assoc.org if you represent this Research Institution and have identified any required additions or modifications to the above information.