An Experimental Study on the Shear Performance of Fully Encapsulated Cable Bolts in Single Shear Test

A set of single shear tests on fully encapsulated cable bolts was carried out using a newly developed and integrated Megabolt single shear apparatus. The instrument is designed to determine the pure shear strength of cable bolts where there is no contact between the host body faces during the shearing process. Eight different types of cable bolt were encapsulated in 40 MPa concrete cylinders, using Stratabinder HS grout. Prior to encapsulation, cable bolts were pretensioned at the desired value using a manual pretensioner. Effects of surface profile, pretension value and debonding on shear strength of cable bolts were investigated. It was found that the shear strength of spiral/indented cable bolts was lower than that of plain cable bolts. Increasing the pretension load decreased the peak shear load of cable bolts. In general, no debonding was observed for spiral/indented cable bolts during shear testing; however, all tested plain cable bolts were debonded.