Experimental Study on Determining Design Parameters of Non-Prestressed BFRP Anchor for Supporting Soil Slope

Abstract

Basalt fiber-reinforced polymer (BFRP) is a high-strength, lightweight material with an anti-corrosion property and a thermal expansion coefficient that is close to that of concrete. When used as an anchor bolt material, the corrosion problem of steel anchors can be solved fundamentally. In recent years, the BFRP bar has been applied in geotechnical anchorage engineering. In this study, the mechanical properties of the BFRP bar were studied by tensile, shear, corrosion resistance, and bonding strength tests with cement-based materials. In accordance with the design specifications of the steel anchor and existing research results, the design parameters of the non-prestressed BFRP anchor in supporting soil slope were proposed. To examine the reinforcing effect of the BFRP anchor, this study adopted the recommended parameters to design a BFRP anchor in an actual soil slope. A field contrast test of the steel anchor was also carried out. Experimental studies yielded the following conclusions. First, the tensile-strength safety factor of the non-prestressed BFRP bar should not be less than 1.6 (permanent) and 1.4 (temporary). The tensile-strength standard value was 80% of the ultimate tensile strength, and the value of the BFRP bar (diameter ≥ 12 mm) commonly used as an anchor was 710 MPa. The bonding-strength standard value between the BFRP bar and cement was equal to the average value divided by 2.1 of the pull-out test, and the common value was 2.8 MPa. The monitoring field test data proved that the designed BFRP anchor demonstrates better control displacement and can effectively retain soil slope. Moreover, the reinforcing effect of the BFRP anchor was equivalent to that of the steel anchor. Thus, the design of the BFRP anchor is reasonable, and the equal strength substitution method can be used to design the BFRP anchor.