Research On Application Of FBG Sensor Technology In Landslide Monitoring

Pipeline landslide poses a grave security threat to security of pipelines. In view of pipelines laid in landslide mass, a combinative monitoring method based on Fiber Bragg Grating sensors is proposed in this paper. This method adopts FBG strain tubes to monitor landslide displacement and FBG strain sensors to monitor pipe stress. This method has been put into practical application in Erlangmiao Landslide Monitoring Project. The main research works and results include:Firstly, after analyzing present landslide monitoring methods, a combinative monitoring method for pipeline landslide based on FBG sensing is proposed. FBG sensors characterized in anti-electromagnetic interference, corrosion resistance, good stability, high sensitivity, small dimension, light weight and low cost are selected to monitor landslide displacement and pipeline stress. According to actual application, this monitoring method is stable, reliable, cost-saving and easy to realize automatic real time monitoring.Secondly, considering the need of long-term pipeline landslide monitoring, FBG strain tubes for monitoring landslide displacement in deep positions, temperature self-compensation FBG strain sensors for monitoring pipeline stress as well as FBG soil pressure sensors for monitoring pipeline interface soil pressure were developed. And performance parameters of the sensors have been obtained after experiments and researches.Finally, the monitoring method has been applied to Erlangmiao Pipeline Landslide Monitoring Project to monitor landslide and pipelines by combining FBG strain tubes and temperature self-compensation FBG strain sensors; data gained after 5.12 Wenchuan Earthquake were analyzed in details and the results indicate that the sensors are of stable performance; stress of pipeline increased obviously after the earthquake but are less than pre-warning threshold, so the pipelines are in safe condition; when motion of the landside mass as a whole is happening, relative motion happens to the parts and is more clear in the direction of the main slide line; therefore, pipeline landslide combative monitoring method based on FBG is feasible and has potential of anticipation result.