Development of borehole multiple deformation sensor system

Kashiwai, Yoshio*; Daimaru, Shuji*; Sanada, Hiroyuki; Matsui, Hiroya 

The multiple deformation sensor system for small diameter borehole is required for the monitoring of high-level radioactive waste disposal site. The conventional monitoring systems are only available to the large borehole and only available for 6 or less measurement sections. The Borehole Multiple Deformation Sensor System was developed based on the FBG sensor technology that can be set in a 66 mm diameter borehole and available for 9 or more measurement sections. This sensor consists of deformation sensor units of three ranges; 50 mm for shallow part, 7 mm and 1 mm for deep part from tunnel wall. These sensor units for deep part also have the self compensation function for the temperature variation. The developed sensor system is applying for the monitoring of ground deformation in the Horonobe Underground Research Center.