MECHANICAL BEHAVIOR OF FULLY-GROUTED BOLT IN JOINTED ROCKS SUBJECTED TO DOUBLE SHEAR TESTS

Abstract

To analyze performances of the fully-grouted bolt in jointed rocks, the double shear tests were conducted, and the analytical derivation to the relationship among axial force, shear force and shear displacement of the fully-grouted bolt were carried out by using the simplified mechanical model. Finally, the sensitivities of the influence parameters of the bolt were analyzed. The results show that the shear force predominates in the shear test and the shear force is much greater than the axial force. The shear force of the fully-grouted bolt increase with the shear displacement increasing and the relationship curve of shear force and shear displacement can be simplified into five stages: steep increase, slight decline, slow increase, slow decline and sharp decline stages. Similarly, the axial force and shear displacement curves can be simplified into three stages: stable increase, steady and sharp decline stages. The simulation results show that the confining pressure on the shear strength of the bolt is the most significant factor, the strength of the jointed rock is the second, and the jointed surface parameters have the least effect. The conclusions obtained in the study are of important theoretical value to direct the similar engineering practice. Keywords: Double shear test, Fully-grouted bolt, Axial force, Shear force, Numerical simulation