In the scientific theme of nuclear waste/CO2 geological disposal or shale gas, the biogeochemical, hydrogeological, thermal and mechanical processes in the subsurface system will be critical controls on chemicals transport. The strong interactions between these processes have been observed in experiments and we aim to develop a novel overarching and well-constrained theory for the coupled process in the system and generate new mathematical and computational modelling with the application on Geoenergy or Geotechnical Engineering.
Artificial Intelligence (AI) has attracted considerable attention from Civil Engineers over the last decade. However, traditionally, AI have been trained using input and output datasets with simple loss functions, which incorporate no physical system knowledge into the learning process, while requiring huge amounts of data, which are either costly to produce or unavailable. Our research will integrate fundamental physics into the training process of deep learning processes, engaging computational modelling and deep neural network, and establish a new generation of physics-informed deep learning methods.
Cavity expansion theory is an important branch of theoretical methods in geomecahnics. It is concerned with the stress and displacement fields around cavities embedded in either linear or nonlinear media. Over the past 70 decades, cavity expansion theory has found many applications in the analysis and design of a variety of geotechnical problems, such as in-situ soil testing, deep foundations, tunnels and underground, piles and plate anchors.
•Many pieces of research have been established to develop a good modelling approach that can analyze and simulate the carbon dioxide injection process (in supercritical and gas phase). However, little research has been done on a fully coupled relationship. The mixture coupling theory approach developed to capture fluid transport in deformable porous media is a good base for developing such a model. A fully coupled Thermo-Hydro-Mechanical-Gas-Chemical (THMGC) model based on the mixture coupling theory approach is developed in this research.
Steel Corrosion
The corrosion issues triggered by CO2–H2O system is one of the major challenges in the petroleum industry. The accurate and comprehensive prediction of the corrosion rate is crucial for pipeline design and operation. CO2 corrosion happens as a result of the coupled actions of various processes, such as chemical reactions, electrochemical reactions and the mass transport of involved species driven by diffusion, electro-migration and convection. Moreover, the formation of a protective iron carbonate layer in CO2 corrosion of steel can protect the substrate against corrosion, which should be incorporated in the CO2 corrosion prediction model. Thus a coupled corrosion prediction model of carbon steel is developed in high-PT CO2 environments.
Sewage sludge contains valuable nutrients and organic matter, which are increasingly being applied to agriculture. Unfortunately, it also contains low concentrations of metals, so repeated application is leading to the gradual accumulation of metals in soil, which could cause serious environmental and health risks. Also, the risks posed by metals in soil is strongly dependent on their speciation. Therefore, information on the speciation of metals in sewage sludge applied to land is required for its land management planning and risk assessments. The aim of this project is to determine the behaviour of metals in sludge-amended soil during repeated cropping cycles. This will allow prediction of the evolution of metal speciation in sludge-amended soil and inform the risk assessments for sewage sludge application to agriculture.
Turning renewable energy sources into hydrogen by electrolytic water hydrogen production technology and using hydrogen as an energy carrier for storage and transportation provides an effective way to solve the above problems. As an emerging technology, blending hydrogen into the existing natural gas pipelines can achieve large-scale hydrogen transportation at a lower cost, and is attracting more and more attention. Hydrogen can be adsorbed on the surface of the steel and permeate into the steel, which is the primary cause of hydrogen embrittlement. Thus the coupled thermo-hydro-mechanical-chemical modelling is applied to develop a hydrogen diffusion model, and in-situ high-pressure gaseous hydrogen permeation tests are conducted to validate the model. The modelling results can provide useful references for the material design for hydrogen pipelines and containers.
Based on the mixed coupling theory, a multi-field coupling mathematical model of underground migration of shale gas fracturing pollutants is established. The multi-field coupling numerical calculation model of underground migration of shale gas fracturing pollutants is constructed. The migration process of target pollutants under the action of complex multi-physical fields during fracturing is quantified, and the migration range of pollutants and the impact of groundwater environment are predicted.
The realm of Biogeotechnics is an interfaces between microbiology, geotechnical and environmental engineering. The current focus is on understanding the natural bio-mediated processes in the geoenvironment, assessing their impact on geomaterials, and anthropogenic application of these processes in real life scenarios.