RUB Research School

Development of a numerical model for the description of the path-dependent swelling behaviour of clayey materials

The Research Project

The disposal of nuclear in so-called deep geotechnical repositories is one of the most challenging missions in current geosciences. An impermeable soil and rock barrier is needed to protect our natural resources against contamination from the sources of emission. Expansive clay materials are suited for the barrier due to their low hydraulic permeability and swelling capacity, which prevent a possible migration of contaminated water and even selfheal dangerous cracks in the buffer. In the design of repositories, numerical simulations help to predict the performance during the functionality period of the barrier estimated at 1 million years, but existing material models and simulation techniques are reaching their limits in predicting the coupled hydro-mechanical behavior due to complex boundary conditions. In my research, I am aiming to develop a new model based on an experimental campaign that investigates numerous combinations of hydro-mechanical loading paths, with special attention to the material’s loading history. The novel aspect of my proposed model is to consider the water bound by the swelling process as a separate phase with its own properties and hydro-mechanical contribution to the overall behavior. The material model will be implemented in an advanced in-house finite element software for coupled geotechnical simulations to model the holistic material behavior with less compromise and validate the experimental results.

IRB Funded Activities

Participation in Workshop of the Swiss National Cooperative for the Disposal of Radioactive Waste (September 2021)

In September 2021 I joined a workshop on Engineered Barrier Systems and Bentonite properties and applications, organized by Nagra, the Swiss National Cooperative for the Disposal of Radioactive Waste. The workshop took place in one of Nagra’s Underground Rock Laboratories located in the swiss alps just below the Grimsel Pass at an elevation of approx. 1700 m. As well as seeing Nagra's large-scale experiments in the rock laboratory, we were treated to a week of lectures and discussions by internationally recognised experts in the field of nuclear waste disposal. Both the participants and the speakers came from different disciplines, which made for a very open and fruitful exchange during the week-long workshop. The informal setting of the event made it very easy to make contacts, so that it was a great introductory event for me on the international level. I am grateful that I was able to realise this activity with the help of IRB funded by RUB Research School!

10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE 2023) at Imperial College London, on 26 - 28 June 2023.

The conference series “NUMGE” is the most prestigious conference about Numerical Methods in my field of studies, hosted by the European Regional Technical Committee 7 for Numerical Methods (ERTC7) and the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE). After a pandemic caused delay, finally the 10th Edition took place this June at Imperial College in London with three days of exciting and inspiring lectures by experts and scientists from all over the world. The funding by IRB enabled me to present the progress of my PhD project in front of a renowned audience, to exchange ideas with fellow scientists during coffee breaks, to get feedback and new input about my work. The setting of Imperial College London an the city in general made this conference very special - including a conference dinner on the River Thames!