Internal deformation monitoring for centrifuge slope model with embedded FBG arrays

The fiber Bragg grating (FBG) sensing technology was utilized for internal deformation monitoring in a centrifuge test of soil slope. An array of FBG sensors were encapsulated into a sensing fiber with a diameter of 0.9 mm. A pullout test was designed to investigate the frictional behavior between the sensing fiber and soil. It was concluded that, for a certain value of overburden pressure, the fiber strain is equal to the strain of soil as long as the fiber strain is less than its peak value in the pullout test. The sensing fibers were embedded directly into a slope centrifuge model to monitor the internal strain distribution and its variation. It can be found that the horizontal sensors were stretched extremely and the vertical sensors were compressed distinctly near a potential slip surface. Thus, it is possible to evaluate the soil internal deformation as well as the failure of the slope model by using FBG sensing technology. This is verified by a comparison between the results of FBGs and that of a numerical simulation. According to these preliminary results, discussions and recommendations for further research are presented.