Distributed Fiber Monitoring Test and Its Application to Slope Deformation

Brillouin Optical Time-Domain Reflectometer(BOTDR),a newly developed distributed fiber optic sensing technique,has some unique functions such as distributed,long distance,anti-electromagnetic interference,and waterproof,and is very suitable and useful to the monitoring and early-warning of geological engineering such as slope engineering.There have been many tests and practices of which the distributed fiber optic sensing technique had been successfully applied to geotechnical engineering.However,for a soil slope,the layout of fiber sensors will greatly affect the monitored data.In this paper,the experience of lab tests and practical applications that BOTDR was applied to monitor the deformation of a soil slope were introduced.In a case of the reinforced soil slope,the fiber sensors were tried to be embedded into soil anchors and frame beams,which shows the result of strain can well reflect the deformation cha-racteristics of the slope.Another case of a highway slope,the fiber sensors were directly buried into a shallow soil layer of the slope,the location of strain anomalies in monitoring data can well reflect the location of soil surface failure,but this method does not fit for long time monitoring,because too much deformation of fiber sensor will cause fiber sensors broken down.And a lab test in which fiber sensors were embedded into geotextiles used for slope reinforcement were also introduced in this paper,which shows the monitoring results were mainly affected by the type and the layout of the fiber sensors,and the properties of the geotextiles.Lab tests and engineering practices show that the distributed fiber optic sensing technique can be well used in slope safety monitoring through proper layout method and data processing.At last,the prospects and future key issues were discussed.