A Numerical Method for the Design of the U-Shaped Segmental Tunnel Lining under the Impact of Earthquakes: A Case Study of a Tunnel in the Hanoi Metro System

Abstract

Circular tunnels are usually encountered when excavation tunnel. However, the U-shaped tunnel lining is used a lot in practice because of it’s advantages. However, there are not many studies in the world to calculate and design for underground structures with U-shaped tunnel lining, especially in the case of tunnels being affected by earthquakes. This paper proposes a new numerical-HRM method approach for the analysis of U-shaped segmental tunnel lining under the impact of earthquakes. Hanoi is the capital of Vietnam, this is a big city with more than 8 million people. Hanoi is located between two major fault systems, the Red River fault system and the Son La-Dien Bien-Lai Chau fault system. Therefore, the Hanoi area is assessed as likely to be affected by earthquakes of magnitude Mw = 6.1 up to 6.5 Richter. The Hanoi metro system is constructed by TBM and the U-shaped segmental tunnel lining is also one of the types of tunnel lining considered for use in the construction of metro tunnels in Hanoi. The improved HRM method has been used to investigate the effect of joints in the tunnel lining from the Hanoi system metro under the impact of earthquakes is conducted considering from the results of the tunnel lining behavior in terms of bending moment (M), normal forces (N) and tunnel lining displacements (δn) in both cases: the U-shaped continuous tunnel lining and the U-shaped segmental tunnel lining.