Abstract: The glass fiber reinforced plastics(GFRP) anti-floating anchor is one kind of new materials which bonds by the resin and the glass fiber. Compared with the steel bar anchor rod, it has the high specific strength, nonelectric conductivity, nonmagnetic nature and corrosion resistance. Based on the full-scale drawing destructive field tests of six GFRP anti-floating anchor and four steel bolts, the load-bearing characteristics and interface bond properties of GFRP anti-floating anchor in moderately weathered granite are studied. By the test results, several conclusions are drawn: (1) There are two failure modes of anti-floating anchor as follows: shear failure between the anchorage rod and grout; and shear failure between the grout and surrounding rock mass. (2) Under the condition of M32.5 grout and the anchorage length with 2.0 m, ultimate anti-lifting bearing capacity of GFRP anti-floating anchor and steel bolt with diameter of 28 mm are 225 kN, ultimated anti-lifting bearing capacity of GFRP anti-floating anchors with diameter of 32 mm is 250 kN, which can be satisfied with engineering demands. (3) The average bond strength between GFRP anti-floating anchor and grout (the first interface) is 1.50－1.54 MPa; (4) The average bond strength between the grout and surrounding rock mass (the second interface) is 0.32－0.37 MPa, which is slightly lower than the average bond strength of the second interface of steel bolt; (5) The average bond strength of the second interface of GFRP anti-floating anchor with diameter of 32 mm is higher than GFRP anti-floating anchor with diameter of 28 mm. According to the test results, the probable failure form and mechanism of GFRP anti-floating anchor are further analyzed. The research results can provide theoretical basis for application of GFRP anti-floating anchor.

Key words: moderately weathered granite, full-thread GFRP anti-floating anchor, ultimate anti-lifting bearing capacity, first interface；second interface