FBG sensor network in Qinghai-Tibet Railway

In this paper, fiber Bragg grating (FBG) sensors network in the subgrade temperature monitoring system in Qinghai- Tibet railway is presented. The principle of the FBG temperature sensor is introduced and the feasibility of the FBG sensors in the permafrost regions of Qinghai-Tibet plateau is analyzed. The FBG sensor network architecture is introduced. This sensor network includes the sensor chains embedded in the roadbed, slave optical cables, work stations including the FBG sensor interrogator and the optical router, master optical cables, and center workstation. We give the primary experimental result of this sensor network in monitoring the roadbed temperature of the railway at DK0985+000 near Chumar River. Fifteen FBG temperature sensors were embedded into the roadbed monitoring hole. The temperature data was collected after a month when the temperature field in the monitoring hole is stable. The result of the experiment shows that the FBG temperature sensors have an accuracy of 0.1 centigrade. Furthermore, the experimental result shows the stability and reliability of the FBG sensor network in the harsh environment of Qinghai-Tibet plateau. In the end, the conclusion is drawn and the prospect of the FBG sensor network in monitoring other parameters in the Qinghai-Tibet plateau is also presented.