Abstract:

Due to the long stabilizing time of the crosspassage structure constructed by freezing method, the health monitoring becomes an important method to guarantee the safety of the crosspassage. Firstly, based on the Xiamen Subsea Tunnel crosspassage project, a realtime monitoring method for frozen soil, crosspassage structure and the shield tunnel structure of crosspassage project of Xiamen Subsea Tunnel is proposed by using fiber grating sensing technology. And then, the interaction between the structure and frozen soil of different construction phases is studied; the health monitoring indices and monitoring methods for freezing construction phase and normal service phase are put forward based on the stress characteristics of the crosspassage structure. Finally, the health monitoring and evaluation system of the crosspassage structure is established. The results show that the monitoring indices and methods varying with construction and operation two phases, can effectively evaluate the safety performance of the structure and guarantee the safety of the crosspassage.

Key words: subsea tunnel, freezing method, crosspassage, health monitoring, fiber grating strain gauge