Dr Yao is a Professor at Beihang University, Beijing, China. He is Vice Chairman of the Soil Mechanics and Geotechnical Engineering Branch of the China Civil Engineering Society and Deputy Director of the special Committee of Geotechnical Mechanics, Chinese Society of Mechanics. His research interests include geotechnical constitutive theory, the application of constitutive theory in numerical calculations and geotechnical problems in airports, highways and railways