An Experimental Study on Thermal State Monitoring for Permafrost Roadbed of Qinghai-Tibet Railway Using DTS

摘要

The free water content in frozen soil is greatly influenced by its thermal state. Once the ice in frozen soil starts to thaw out, the soil structure will be loosed and its strength will greatly decrease. A distributed temperature sensing (DTS) system is suggested to monitor the thermal state of permafrost roadbed of Qinghai-Tibet railway in order to prevent the non-homogeneous thaw settlement of permafrost roadbed in this paper. An experimental study using DTS based on Raman optic time domain reflectometry (RODTR) was carried out to investigate the application feasibility of DTS for thermal state monitoring for permafrost roadbed. The experimental results indicate that the distributed temperature field of frozen soil along the optical fiber can be easily monitored in real time between the temperature of -24.6℃ and 27.2℃, and the temperature rising event along the cable can be clearly distinguished by DTS. It is expected that DTS based on ROTDR has great potential in thermal state monitoring for permafrost roadbed of Qinghai-Tibet Railway.