Interface Shear Behavior between Soil and Microbial-Stimulated Piles

Objective

"This interdisciplinary research addresses critical challenges in offshore wind foundations by developing MICP technology to reinforce the soil-pile interface. Offshore foundations suffer from frictional resistance degradation due to particle breakage during installation (large displacement shear) and operational phases (long-term cyclic shear), reducing bearing capacity and service life. At this stage, it is impractical to dismantle piles, increase pile length, or expand pile diameter. Therefore, in-situ reinforcement presents a feasible alternative. Current cement/polymer-based binders raise sustainability concerns, prompting the exploration of environmentally friendly MICP technology, which utilizes bacteria to precipitate CaCO3, enhancing cohesion, reducing shear band thickness, and improving dilatancy while minimizing disruption. Main objectives include: 1 explore the macro-micro mechanism governing strength of soil-pile interface; 2) develop a hypoplastic interface model considering MICP’s cementations; 3) clarify the resistance transfer mechanism and failure mode of MICP-reinforced interface, propose a reinforcement quality control strategy; 4) develop a real-time monitoring technique suitable for interfaces. Milestones span 24 months with five key deliverables including journal papers, code, patent, and protocol. WP1 will analyze coupling between cyclic interface shear and MICP cementation, and develop a hypoplastic constitutive model integrating MICP parameters. WP2 will propose an interface reinforcement technology and a quality control protocol. WP3 will validate reinforcement effects using a large-scale shear device, correlating acoustic signals with CaCO3 content for real-time monitoring. By bridging microbial stimulated method and marine engineering, this research pioneers ""alive"" soilstructure interfaces, offering a sustainable pathway toenhance offshore wind infrastructure resilience against climate challenges while reducing CO2 emissions."