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.