Soil deformation measurement based on optic fiber sensor

A double-coating optical fiber sensor which is used for soil deformation measurement is proposed in the paper. It could be used in non-destructive detection of large scale structures, health evaluation of the civil structures and forecast of geologic hazard such as landslide. The structure of the double-coating soil mechanical sensor is designed and the mechanical model of the mutual effects between the optical fiber and the soil is founded. Under the static press, the deformations of the soil dam model and the slope model are experimentally detected by using the calibrated white-light fiber soil mechanical sensor. In the experiment, a 500 millimeter length double-coating soil mechanical sensor is chose to detect the soil deformation. Measuring results indicate that the mechanical transfer coefficient is 0.31 and the measuring range of deformation is from zero to 10 millimeter. Compared with the outside stickup sensors, the embedded soil mechanical optical fiber sensor can faithfully represent the deformation inside the soil model, the measuring result is closer to the real soil deformation and the measuring method is more effective.