Professor Jun Yang of the Department of Civil Engineering in the HKU Faculty of Engineering has been honoured with the State Natural Science Award (Second Class Prize) for his outstanding contributions to scientific and technological progress. The official announcement was made on July 8 at the National Science and Technology Award Conference, and the General Assemblies of the Members of the Chinese Academy of Sciences and the Chinese Academy of Engineering held in Beijing.
From ground motion to the dynamic properties of geomaterials, from theoretical models to laboratory testing, Professor Yang and his team have a deep interest in a range of problems in soil dynamics and earthquake engineering.
The research he leads aims to advance the fundamental understanding of the complex behaviours of earth materials and to develop better solutions to major engineering problems, such as natural hazards and mitigation and the infrastructure systems for sustainable development.
As a natural material, soil exhibits highly complex mechanical behaviours under stress. Professor Yang’s award-winning research project, ‘Anisotropic State-Dependent Theory and Constitutive Modelling of Soils’, provides an in-depth exploration of this challenging problem. In its natural state, soil exhibits a distinct ‘anisotropy’ – meaning its physical properties and strength vary significantly depending on the direction of the applied force or measurement. This behaviour is further compounded by ‘dilatancy’, a phenomenon where soil actually expands in volume as its internal particles reorganise under compression or shear forces, closely intertwining changes in volume and shape. Together, these unique characteristics make soil behaviour under stress difficult to predict, posing a major, long-standing safety challenge for geotechnical engineering projects worldwide.
This award-winning research systematically decodes the relationship between soil anisotropy and its physical state. The team successfully established mathematical equations capable of simultaneously and precisely describing both ‘generalised dilatancy’ (volume expansion under shear forces) and the ‘hardening process’ (the gradual increase in soil strength under loading). Building on these equations, the team rigorously proved the existence and uniqueness of the ‘anisotropic critical state’ – the ultimate boundary where soil reaches a stable, continuous deformation regime – and defined the exact physical conditions under which anisotropy can coexist within this state.
By establishing this comprehensive theoretical framework, the team developed a series of advanced ‘constitutive models’ (mathematical models used to simulate how materials deform under stress). These models provide highly accurate predictions of soil strength and deformation, offering a reliable scientific foundation and predictive tool for tackling complex geotechnical engineering challenges.
“I am honoured to receive this prestigious award alongside my two distinguished collaborators,” said Professor Yang. “I would like to express my sincere gratitude to the University of Hong Kong for providing a supportive research environment, and to the Research Grants Council of Hong Kong for their financial support over the years. Their support has enabled me to focus on addressing important and fundamental research questions.”
Conferred by the State Council of the People’s Republic of China, the State Science and Technology Awards are prestigious honours in the Chinese Mainland’s science and technology fields. They recognise individuals and organisations that have made outstanding contributions to scientific and technological progress. This year, 258 projects were selected, including 51 for the State Natural Science Award (three First-Class Awards and 48 Second-Class Awards).
