Measurement of Load Transfer between Anchor and Grout using Optical FBG Sensors embedded in Smart Anchor

FBG 센서가 내장된 스마트 앵커를 이용한 앵커와 그라우트의 하중전이 측정

FBG Sensor, which is smaller than strain gauge and has better durability and does not have a noise from electromagnetic waves, was adapted to develope a smart anchor. A series of pullout tests were performed to verify the feasibility of smart anchor and find out the load transfer mechanism around the steel wire fixed to rock with grout. Distribution of shear stresses at steel wire-grout interface is assessed from the measured strain distribution by the optical fiber sensors and compared with stress distributions predicted by Farmer's and Aydan's formulas. It was found that present theoretical formulas may underestimate the failure depth and magnitude of shear stresses when the pullout loads increase.