In order to study failure problem of glass fiber reinforced plastics (GFRP) bolts under blasting dynamic load

this study establishes a numerical model of full-length mortar anchored GFRP bolt using FLAC software. The stress and failure characteristics of the bolt

bolt-mortar interface

and mortar-rock interface under pre-tension static load and blasting dynamic load are investigated

and the influences of dynamic load intensity

surrounding rock strength and mortar strength on bolt stress are analyzed. The reliability of the research results is verified in comparison with the existing experimental results. The results show that the maximum axial stress of GFRP bolt increases linearly with the increase of dynamic load intensity and decreases with the increase of surrounding rock or mortar strength

and the axial stress distribution of GFRP bolt is more concentrated than that of metal bolt. The shear stress of the two interfaces increases rapidly to the peak along the bolt

and then decreases to zero. After that

the interface with relatively weak bonding properties is debonded at first

and the shear stress at the debonding position decreases to the residual bond strength. Meanwhile

the peak shear stress shifts to the bottom of the hole. The shear stress distribution of GFRP bolt is more concentrated than that of metal bolt

and the peak position is more prominent. The greater the dynamic load intensity

the larger the debonding length and shear stress distribution of the failure interface

and the peak position of the shear stress of the undamaged interface will be transferred to the bottom of the hole. The greater the surrounding rock strength or the smaller the mortar strength

the more likely the shear failure occurs at the bolt-mortar interface; on the contrary

it is more likely to occur at the mortar-rock interface.