An innovative bar-type fiber optic displacement sensor based on fiber Bragg grating (FBG) technique was developed to overcome difficulties of conventional methods used to monitor internal displacement fields within a small-scale geomechanical model. An FBG array sensors was attached to a plastic bar and laboratory calibration of the apparatus was performed. Three sensors were installed into a three-dimensional model simulating the underground excavation of the Shuangjiangkou hydro-power station. The sensors were installed with a pre-grout method. Calibration and model tests show that the displacement sensor accurately measures displacement profiles along the bar length. The strain data from the FBG sensors provides the information used to derive the displacement profile. Horizontal displacements during excavations near the main power house and the surge chamber are within a small range and the excavation activities are demonstrated not to affect the overall stability of the structure.
|Number of pages||5|
|Journal||Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology|
|Publication status||Published - Nov 2010|
- Fiber optic displacement sensor
- Geomechanical model test
- Underground excavation