BOTDR-based pull-out tests on anchor bolts

Monitoring of the stress distribution along anchor bolts is a critical issue for ground anchorage engineering.Considering the characteristics of distributed fiber optic sensing technology—Brillouin optical time-domain reflectometer(BOTDR),the layout and installation of the sensing fiber on anchor bolts were designed.Combining the pull-out tests on anchor bolts,the feasibility of this method was discussed.The test results demonstrated that BOTDR-based distributed fiber optic sensing technology had some unique advantages,such as easy installation and large measurement range.It could veritably detect the axial strain and stress distribution of the anchor bolts under different levels of load.Thus the conclusion could be drawn that BOTDR-based distributed monitoring technology had wide application prospect in geotechnical engineering.