Abstract:

The principle of optical fiber sensing technology, the composition of optical fiber sensing system and the application of optical fiber sensing technology in the monitoring of urban Metro works are presented, with the case of Xiaobei station on Line 5 of Guangzhou Metro as an example. The analysis on the temperatures, the concrete strain rules and the monitoring results of the rebar strain gauges demonstrates that optical fiber sensors are corrosionresistant, rapid in reaction and stable in data transmission. Furthermore, optical fiber sensors can detect the subtle variations. It is concluded that optical fiber sensing technology will be widely used in the monitoring of underground works in the future. However, it is the first time that optical fiber sensors are used in the monitoring of underground works, some problems, such as improper selection of monitoring points, crosssensing of the optical fiber sensors to strains and temperatures and insufficient protection of the monitoring points, still exist.

Key words: optical fiber sensing technology, Metro, monitoring