Comparative study on foundation treatment methods of immersed tunnels in China

Based on engineering practices of four typical traffic immersed tunnels built in China,this paper details the features of the four dominant foundation treatment methods for immersed tunnel construction:pile foundation,sand flow foundation,grouting foundation,and gravel bedding foundation.Subsoil stress time-history of different method are specified first,plus a summary of settlement assessment method for foundation quality control.Further,a comprehensive comparison of settlement and cost of these four foundation treatment methods is conducted to highlights the specific merits,disadvantages and conditions encountered in each foundation treatment method,based on real projects information.The findings of this article could henceforth be applied to foundation treatment work in immersed tube tunnel construction.