Joining the 2nd GAS/HITEC Joint training course – Liège (Belgium) – August 28th to September 1st 2023.

Geomechanics plays a significant role in the understanding of the multiphysics and multiscale processes taking place in a geological disposal facility for radioactive waste. The objective of the training course is to introduce state-of-the-art understanding, concepts and methods related to thermo-hydro-mechanical coupled processes, the physical impacts of thermal loading and the mechanistic understanding of gas migration in geomaterials. Basics of thermo-hydro-mechanical processes in geomaterials were introduced first. Many valuable methods and skills on the numerical modelling of thermo-hydro-mechanical processes were presented in detail. For example, the appropriate order of conducting thermo-hydro-mechanical modelling was shown in the presentation. Then the basics of experimental testing of geomaterials was presented. Some basic elastic and plastic theories were introduced at the beginning, and then many experimental facilities and results related to thermo-hydro-mechanical coupled processes were shown. The procedures of some geomaterial experiments were presented in detail. The constitutive modelling of thermo-hydro-mechanical processes in geomaterials was introduced on the second day, and the topic is focused on the theories of thermodynamics and poromechanics. The presentation about the development, validation and maintenance of numerical codes introduced many helpful methods and skills to us, such as how to use Gitlab to store numerical codes and how to use Paraview to visualize simulation results. The Advanced multiphysics modelling of geomaterials including multiscale approaches and heterogeneities was then presented. A number of simulation results, such as the thermo-hydro-mechanical coupled modelling using FEM and the gas migration inside geomaterials using the FEM + Z approach were shown. Besides, the presentation of in situ THM and gas experiments introduced a very long-term barrier experiments including thermos-hydro-mechanical processes, which also introduced the procedure of monitoring long-term experimental data and showed the analysis of the experimental data.