Fig. 1. Sensing structure based on coherent self-heterodyne BOTDR

Fig. 2. Optical fiber sensing structure based on BOTDR

Fig. 3. The setup of the calibration experiment

Fig. 4. The measured strain results of the OFSS and different outside optical cable

Fig. 5. The displacements for different measurement time obtained

Fig. 6. The situ monitoring experiment

Fig. 7. Strain results of OFSS and optical cable by different laying styles

Fig. 8. The displacements in different experiment