Fiber Bragg Grating–Based Flume Test to Study the Initiation of Landslide-Debris Flows Induced by Concentrated Runoff

Abstract

Abstract In order to explore the initiation of landslide-debris flow caused by concentrated runoff, a flume test has been performed on soil samples taken from a debris flow site in Wenchuan earthquake area. The fiber Bragg grating (FBG) technology was used to measure the strain distribution information in the slope mass during erosion. Several hydrological sensors for monitoring pore water pressure and soil moisture were used to investigate their correlation with internal strain field. The test results show that the fiber optic sensing technique exhibited high sensitivity and precision in monitoring the slope deformation. The development of pore water pressures and soil moistures showed reasonable consistency with the dynamics of an infiltration. According to the strain measurements, there were four evolution stages during the initiation of landslide-debris induced by runoff, i.e., the water absorption stage, the deformation stage, the shear zone formation stage, and the fluidization stage. The results provide an improved insight into the mechanism of debris flow initiation and indicate the enormous potential of the FBG sensing technology in establishing an effective early warning system for landslides and debris flows.