Research
Dr Guijie Sang investigates novel biocementation techniques for applications in geotechnical, coastal, offshore, and subsurface engineering. His research focuses on improving the hydromechanical properties of geomaterials (sediments, sands, and rocks), addressing challenges such as coastal erosion, offshore monopile scour, slope instability, and subsurface (wellbore and rock formation) leakage.
Microbially induced carbonate precipitation (MICP)
Guijie has more than five years' experience in using MICP for soil improvement. His work began with studying the transport and attachment of S. pasteurii in sand, alongside monitoring and modelling hydraulic flow and delivering MICP fluids via permeation grouting. These methods successfully transformed loose sand into a “sandstone-like” material with an unconfined compressive strength of approximately 8 MPa. Building on these robust protocols, he scaled the process from centimetre-scale column experiments to metre-scale laboratory trials, and later led a field project with a construction company, applying MICP to natural soil deposits. Guijie has also worked with industrial and public partners on (1) spray-drying storage of S. pasteurii for MICP applications (EPSRC IAA project); (2) optimising bacterial growth (IBioIC project), and (3) in situ bio-stimulation to protect coastal assets from hydraulic erosion (iPACT project).
His current research focuses on:
• Microbial metabolisms for biocementation, including ureolysis, oxidation of organic compound, and carbonic anhydrase-mediated processes.
• Biocementation treatment for sand immobilisation, including erosion and scouring experiments under wind and ocean wave conditions.
• Finite Element Modelling and Simulation, with emphasis on reactive transport of microbes and chemical species during MICP treatment.
Rock Mechanics; Coupled Hydro-Mechanical-(Bio)Chemical Processes
Throughout Guijie's PhD at Pennsylvania State University, Guijie studied hydro-mechanical properties of subsurface rocks (e.g. shale) by investigating water transport and condensation in shale through analysis of sorption isotherms, transport modelling, and in situ small angle neutron scattering (SANS); detecting mechanical damage and failure of shale under cyclic uniaxial loading using in situ ultrasonic monitoring; characterizing gas-sorption-induced rock swelling under reservoir condition; and quantifying rock-brine-CO2 interactions using SANS, and synchrotron X-ray computed tomography (CT).
Guijie's current research interests also include:
• Rock Mechanics and Permeability
• CO2 capture and mineralisation in geological faults
• Geophysical Monitoring (Coda Wave Interferometry, Acoustic Emission)