Geotechnics Section
Supervised by Dr David Taborda and Professor Catherine O’Sullivan
Prior to starting her PhD, Marina completed her MSc in Geotechnics and her bachelor’s in civil engineering, both in Brazil. During her bachelor’s degree, she spent one and a half years at the University of Western Australia, where she developed her final year thesis.
In 2019 Marina was appointed Research Assistant as part of MATHEGRAM, a H2020 Marie Skłodowska-Curie Innovative Training Network (MSCA-ITN), funded by the EU, enabling her to undertake her PhD studies at Imperial College.
Why did you decide to do a PhD in the Department of Civil and Environmental Engineering?
The department was a natural choice for the type of experimental work that I have been developing over the years. During my time in Australia, I discovered Geotechnics and all the challenges and possibilities associated with this field while working in the laboratory of the Centre for Offshore Foundation Systems. Later, this interest was furthered during my master’s degree back in Brazil, which was also mostly developed in the laboratory. Thus, coming from an experimental background associated to the fact that the Geotechnical laboratory facilities at Imperial are world-leading, choosing Imperial was an easy decision. I addition to that, the strong postgraduate research programme in the Department of Civil and Environmental Engineering seemed ideal to pursue my doctoral studies, and further my technical skills.
Tell us about your PhD research
My research focuses on the thermal behaviour of granular geomaterials (i.e., sands and gravels). Geomaterials are commonly exposed to thermal loads induced by natural phenomena (e.g., seasonal weather changes) or by human-made structures such as highway pavements, nuclear waste repositories, oil and gas pipelines and power cables. Geothermal (or ground-source) energy systems, which can effectively heat or cool the internal environment of buildings, are of particular interest to our research.
Soils are usually classified as either fine (e.g., clays and silts) or granular and although most of the mentioned structures can be typically encountered in granular geomaterials, little attention has been paid to the systematic characterisation of the thermal effect on these materials. My research intends to address this gap in knowledge by obtaining a high-quality experimental dataset on the thermo-hydro-mechanical (THM) behaviour of granular materials using the facilities in the Geotechnical Laboratory at Imperial College.
What impact do you hope you research will have/what do you hope your research will lead on to?
With the increasing demand for renewable energy, geothermal energy is emerging as a key technology for future generations; but current models still require data validation. Temperature changes in geothermal applications are usually limited to 40℃, which is within the range of the equipment in our facilities. Our on-going research attempts to experimentally establish the micro-to-macro behaviour of these materials subjected to temperature changes. With the proposed new methodology, specifically developed to interpret saturated tests at higher temperatures, we expect to explain the link between the overall behaviour of tested specimens and the changes in the internal arrangement of particles – which is usually expressed in terms of voids. Due to the inexistence of standards for non-isothermal tests, we expect to develop rigorous protocols to perform and control tests, as well as the intrinsic error associated to measurements.
Because my research is more of a fundamental nature, the next step would be translating this understanding of the THM behaviour of granular materials into constitutive models for large scale simulations of geotechnical structures.
Does your research involve working with collaborators outside of the Department? If so who and why?
To a certain extent, my research involves the collaboration with other Early-Stage Researchers that are also part of MATHEGRAM, a multidisciplinary consortium that includes 15 individual projects distributed among 10 institutions in the EU and the UK. Since the combination of all the individual projects aims to address the same fundamental research questions, the exchanging/sharing of different solutions and approaches are common during our meetings, seminars, and training courses. Therefore, such collaboration provides the opportunity for us to achieve our individual goals while, simultaneously, it also contributes to the broader picture.
What is a typical week like for you?
Working in the lab means that a typical week is hard to define. The unpredictable nature of experimental work makes one week very different from another; sometimes a quiet week filled with the expected on-going tests can be instantly replaced by consecutive setbacks, which can strongly affect our schedule. In general, though, a “typical” week obviously involves most of my time being spent in the lab, either preparing specimens and running tests, or focusing on post-processing data and searching for evidence in the literature. However, there are moments during the week dedicated to high-quality discussions with my peers, my weekly meetings with my supervisor, as well as my Scout weekly meeting after work on Tuesdays.
How have your skills developed, both professional and personal?
The Graduate School offers a variety of courses that range from technical and communication skills development, exploring the impact of research, all the way to professional progression – which includes next steps on our career plan. I have taken many courses, especially the ones more focused on technical skills that include programming, data visualisation, statistics, and data and management skills. The PhD daily life also provides countless opportunities to hone our soft skills, which I’m confident will be of fundamental importance after finishing my studies.
Since MATHEGRAM is multidisciplinary, it’s very common for me to communicate with researchers coming from different cultural and scientific backgrounds. Although it sometimes can be challenging, this constant exchange has definitely led me to communicate more clearly and objectively. MATHEGRAM is also inter-sectoral, and Early-Stage Researchers are expected to experience working in industry through an industrial secondment. During my on-going industrial secondment, I have gained and developed new skills, which can be successfully transferred and applied to my studies.
What do you enjoy most about being a PhD in the Department?
I’m very passionate about research in general. It is an experience that has always fascinated me, especially for the rich and in-depth discussions with my peers. Imperial College hosts a varied set of brilliant students and staff and my interaction with them has helped my development immensely. This remained true even during the recent COVID pandemic, with different solutions being adopted to mitigate the lack of close personal interaction. Moreover, since our department is involved with cutting edge technological research, the level of challenges is proportionally high, and overcoming such challenges is quite exciting and provides the feeling that our research is meaningful and impacting.