On June 23, 2022, the International Society of Environmental Geotechnology (ISEG) Webinars Series No.2 was successfully held. The speaker of this webinar is Dr. Anh Minh TANG from Ecole des Ponts ParisTech (ENPC), France. More than 1200 people attended the meeting through online meeting room and live broadcast platforms.
First, Prof. Chao-Sheng Tang, the secretary general of ISEG welcomed the guests and delegates on behalf of ISEG president Prof. Bin Shi, and briefly introduced the ISEG Webinar Series (Figure 1). This is a new brand event, in which distinguished experts and scholars in environmental geotechnology in and out the society will be invited to report on the cutting-edge scientific and technological innovations in the field, aiming to widely promote exchanges and cooperation in the frontier fields of environmental geotechnology. Then, Prof. Chao-Sheng Tang introduced the biography of the speaker. Dr. Anh Minh TANG is a Research Director at Ecole des Ponts ParisTech (ENPC). His research interests include unsaturated soils, geological storage of radioactive waste, soil-atmosphere interaction, geothermal energy, transportation geotechnics, and gas hydrate-bearing sediments. He has published more than 140 peer-reviewed journal papers. He serves as editorial board member of several reputable journals in the domain of Geological and Geotechnical Engineering. More than 20 PhD theses have been completed under his co-supervision. He is also a council member of ISEG.
Figure 1 Welcome speech by Prof. Chao-Sheng Tang
Subsequently, Dr. Anh Minh TANG started his report entitled “Effect of temperature in soil mechanics for energy and the environment: some examples” (Figure 2). He presents his research works related to the effect of temperature on soil mechanical behaviour in order to develop geostructures for energy and to increase the resilience of geostructures. Four examples, covering a wide range of temperature was analysed. First, in the concept of geological high-level radioactive waste disposal, soil surrounding the waste canisters may be heated from the initial state (around 10 °C) up to approximately 80 °C. This heating would modify the stress state in soil by increasing pore water pressure and altering soil mechanical properties. Second, in the case of energy geostructures (foundations or buried geotechnical structures which have been equipped with heat transfer pipes so that they may act as ground heat exchanger, part of a ground source heat pump system for heating or cooling of residential, commercial and industrial buildings), soil surrounding geostructures may be cooled down to few °C in winter (for heating demand of the buildings) and heated up to 30 °C in summer (for cooling demand of the buildings). In these conditions, the effect of temperature on soil mechanical properties would be negligible but soil/structure interactions related to thermal dilation/contraction of the structure would be significant. Third, natural gas hydrates abundantly exist within sediment layers along the world’s continental margins (few °C above zero), and within and beneath Arctic permafrost (few °C below zero). Any small change in temperature (due to global warming) would cause this ice-like solid to abruptly separate into water and gas and significantly modify the mechanical properties of the sediment layers. Fourth, for road pavement subgrade in cold region, freeze-thaw cycles related to seasonal change in temperature (variation around 0 °C) can induce degradation by formation of ice lenses related to cryo-suction. After the presentation, several participants had a lively discussion with Dr. Anh Minh TANG on issues of interest.
Figure 2 Dr. Anh Minh TANG in presentation
In the end, Prof. Tang gave a brief summary of the event. He thanked Dr. Anh Minh TANG for his wonderful presentation, and thanked all the guests for their participation. He said that Dr. Anh Minh TANG not only made a wonderful report, but also had profound experience in experimental design and instrument construction, which is worth learning and reference for young scholars. This report has brought many new progress and new ideas, and inspired young scholars in many aspects. In the future, this event will be held periodically. He welcomes everyone to continue to participate in this event and work together to promote the development of environmental geotechnology.
The video record of the whole event can be found on ISEG official Youtube Channel and ISEG official Bilibili Channel.
