Field test of GFRP bar anti-floating anchor slurry-rock interface bonding performance

Abstract

Based on fiber Bragg grating (FBG) sensing and monitoring technology, the slurry-rock interface bonding characteristics of glass fiber reinforced polymer (GFRP) anti-floating anchor and steel anti-floating anchor were investigated through the field pull-out destructive test of GFRP bars and steel anti-floating anchor. The differences in slurry-rock interface bonding properties between GFRP anti-floating anchor and steel anti-floating anchor were defined. In addition, the distribution law of shear stress and axial stress at the slurry-rock interface of the GFRP anti-floating anchor was revealed along the anchoring depth. The results showed that the axial stress at the slurry-rock interface of the GFRP anti-floating anchor is maximum at the hole opening and decreases as depth increases. The axial stress reduces to zero at the anchorage depth of about 2.4 m. The shear stress at the slurry-rock interface increases and then decreases. The slurry-rock interface bonding curve of the GFRP anti-floating anchor is approximately a straight line, while the slurry-rock interface bonding curve of the steel anti-floating anchor is a broken line with an obvious inflection point. Comparing different materials and types of anti-floating anchors indicate that the bond performance of steel anti-floating anchors is slightly higher than that of GFRP anti-floating anchors, and the bond strength of anti-floating anchors’ slurry-rock interface improves with the increase of anchor bar diameter. The synergistic effect among anchor bars, grout, and rock mass of the GFRP anti-floating anchor exceeds that of the steel anti-floating anchor. Using the finite element software ABAQUS to GFRP anti-floating anchor rod on rock interface bonding performance simulation, the simulation results was coincident with the test result.