Abstract: Basalt fiber (BFRP) anchor has many advantages, such as high tensile strength, good corrosion resistance, etc. It is a good substitute for reinforcement in geotechnical anchorage structure, and has attracted much attention in recent years. Four groups of field pull-out tests were carried out in the loess stratum to study the failure modes and anchorage performance difference between the 25 mm diameter BFRP bolts and steel bolts. The results show that the failure signs on inner and outer surface of grouting coexist in the process of drawing for large diameter soil anchor. However, the ultimate failure mode is controlled by the interface between grouting and soil (the 2nd interface), and the damage degree of the interface between BFRP bolt and grouting (the 1st interface) is evidently higher than that of steel bolt. The ultimate bearing capacity of two bolts is similar, and the interfacial bond strength decreases with increasing anchorage length. The bond performance between the steel bolt and grouting is better than that of the BFRP bolt, which is mainly caused by the different processing technology and material mechanical properties between the two bolts. At the same load level and position, the axial force of BFRP bolt is larger than that of steel bolt, and the attenuation rate of axial force is slightly smaller than that of steel bolt; the peak shear stress of BFRP bolt is also smaller than that of steel bolt.

Key words: losses, BFRP bolts, field pull-out tests, bearing capacity, failure mode