Research topic: Centrifuge modelling of a floating elevated energy pile group subjected to non-symmetric thermal cycles in soft clay

I am currently a 3rd-year PhD candidate who is supervised by Prof C.W.W. Ng on the study of energy pile group. Using energy foundations below structures is an effective approach to reduce the energy consumption in recent years. There is not still clear understanding of heating effects on the soil-structure interaction. So, the geotechnical centrifuge modeling is used to investigate the thermomechanical behaviour of energy pile groups. The cyclic heating/cooling in the energy pile group induces excess pore water pressure changes in the surrounding soil within which influence effective stress. Moreover, the temperature changes affect lateral earth pressure conditions on pile-soil interface due to radial thermal deformations in pile, as well as thermal volume changes in soil. These thermally induced phenomena cause cyclic changes in the soil stress and the pile capacity. The consequent plastic strain in the soil causes accumulative irreversible pile settlement. To investigate the problem, the heating/cooling system developed in HKUST is used for centrifuge modelling of energy piles.


Dr Muhammad SHAKEEL

Research topic: Effects of a multi-propped excavation on adjacent floating pile foundations

I am a post-doctoral fellow, after I pursued my PhD in the HKUST in 2020. Underground space has become increasingly important in relieving the shortage of land and meets the transportation requirements in big cities with the rapid economic development and dramatic increases of population. Deep excavations for underground facilities are usually conducted near existing buildings. It is a major concern for designers to estimate potential damages of existing piles resulting from nearby deep excavations. In my research, a series of three-dimensional centrifuge tests are being carried out to investigate the influence of a multi-propped deep excavation on adjacent axially loaded pile foundations in sand and clay. In-flight multi props installation will be simulated using hydraulic actuator which are controlled by pneumatic valve. This research will provide new insight into the fundamental understanding of the soil-pile-excavation interaction mechanism. It is intended to develop calculation techniques and design charts to improve our current design guidelines, which will have significant beneficial impacts on the safety, the environment and the economy worldwide.


Sina Baghbanrezvan

Research topic: Wellbore-sediment interaction during gas production from hydrate bearing sediments

I am from Iran and admitted as a PhD student at HKUST in 2015. Methane hydrates are the most commonly occurring gas hydrates and are typically found in permafrost and marine soil sediments in areas such as Canada, the South China Sea, the Nankai Trough in Japan and the Korean East Sea. Their natural abundance makes them a potential source of energy for the future. The objective of my research is to evaluate the response of methane hydrate bearing sediments in terms of gas and water flow rates and wellbore stability during hydrate dissociation. To achieve this objective, I have developed and built a new energy harvest chamber which can simulate relatively high pressure (up to 14 MPa) and low temperature (2 - 3 °C) environment for hydrate stability.



Research topic: Smart flexible barrier for debris flow mitigation

I admitted to the PhD program in HKUST since 2016. I am working on a project relating to the use of smart flexible barrier as a mean of landslide mitigation. A major challenge of this project is to correctly model the relative stiffness of barrier and the incoming debris flow. In my research, the centrifuge at HKUST is utilized to model the debris volume of 170 m3 in prototype, and its interaction with the barrier of varieties thickness and stiffness. I hope my research will be able to help derive some improved equation for assessing the debris impact force and hence better design the flexible barriers.



Sherif Mohsen GOMMA

Research topic: Centrifuge modelling of energy piled-raft subjected to non-symmetric thermal cycles in clay

I, born and raised in Egypt, obtained his B.Sc and M.Sc in civil engineering at Mansoura University, Egypt. He works as an assistant lecturer at the faculty of engineering, Mansoura University. I am currently in the third year of his PhD in geotechnical engineering at HKUST. In his dissertation, he focuses on the performance of energy piled-raft subjected to non-symmetrical thermal cycles in clay using centrifuge and numerical modelling. I am interested in how the presence of adjacent energy piles affects the serviceability of piled foundations. During his research, he is using the heating and cooling system developed in HKUST to control the cyclic temperature change in energy piles in a centrifuge. Hopefully, my findings will lead to more sustainable and cost-effective designs. Joining the research environment in geotechnical centrifuge facility at HKUST is a good opportunity for me to meet so many bright minds.


Yikai WANG

Research topic: Centrifuge modelling of a floating elevated energy pile group subjected to non-symmetric thermal cycles in soft clay

As a M.Phil student, I am interested in the centrifuge modelling of freezing-thawing effect on the embankment. Frost heave, thawing settlement and crack behaviour are the major concern in my study. Starting from 2018, I developed an in-flight freeze-thaw system within the environmental chamber of the centrifuge. With this device, researchers can gain a deeper insight into the serviceability performance of infrastructures located in challenging ground condition——seasonal frozen soil. Furthermore, when taking account into the climate change, embankments in subtropical area can suffer from freezing-thawing. Maintenance, early warning and design guideline can be provided through my research.


Annie WONG

Research topic: Effects of skew angle on crossing tunnels

I am a PhD student admitted at HKUST in 2017 and am studying tunnelling behaviour using the centrifuge. With urban development and population growth, new tunnels are now constructed in proximity to existing tunnels. With different skew angles, an existing tunnel is subject to stress changes and deformation, which can lead to serviceability problems. Previous studies on multi-tunnel interaction mainly focus on parallel and perpendicular tunnels. The impact on a new tunnel constructed with other skew angle is not well understood. To investigate the complex interaction, three-dimensional centrifuge modelling of multiple tunnels is conducted. Tunnel excavation is simulated three-dimensionally in-flight using a novel device called the “Donut”. The measured results can be back-analysed using the finite element method to enhance understanding of the interaction of multiple crossing tunnels.



Research topic: Effects of root decomposition on slope stability

I am a second-year Ph.D. student from Chulalongkorn University, Bangkok, Thailand, and am currently a research exchange student at HKUST. My research area is on the use of soil bioengineering using vegetation to soil stabilisation. I am working on a project investigating how root decay and decomposition may affect the root biomechanicas, soil hydraulic properties including water retention and hydraulic conductivity function, as well as the slope hydrology and stability under rainfall conditions. The species I am interested in Vetiver grass, which has been recognised to be an excellent candidate for slope stabilisation in the literature of soil bioengineering. This kind of grass was transplanted in the centrifuge strong boxes and then killed to initiate root decomposition. The model slopes, with and without subject to root decay, will be tested under the same precipitations to evaluate their stability.