Early-age behaviour of precast concrete immersed tunnel based on degree of hydration concept

Using the Hong Kong-Zhuhai-Macao Link project as an example, the focus of this research is to describe the early-age behaviour of a precast immersed tunnel using a constitutive model based on the degree of hydration concept. In this way, the effect of both age and temperature on the early-age behaviour can be taken into account simultaneously. Special attention is also paid to early-age creep under varying stress levels combined with the degree of hydration concept. Numerical procedures are proposed to predict the early-age behaviour of immersed tunnel segments during the entire fabrication process. The engineering factors related to early-age cracking are analysed and discussed. This in-depth study results in a better understanding, and further appropriate practical measures can be employed to control early-age cracking in the actual project.