Shearing mechanical model and experimental verification of bolts in jointed rock mass

Based on the principle of the minimum residual energy, the relationship between the horizontal shear displacement of the joint surface and the axial and tangential deformation of the bolt is analyzed considering the shear deformation of the bolts in jointed rock mass. The judgment process of the yield mode of the bolt is determined by analyzing the characteristics of the loading on the bolts. The formula for calculating the shear strength of the anchoring joint surface is established considering the equivalent shearing area, and the accuracy of the theoretical calculation is verified by the indoor physical experiments. The influence of bolt inclination, surrounding rock strength, bolt diameter and normal stress on the shear strength of the anchoring joint surface is discussed. The results show that the shearing mechanical model can better reflect the contribution of the axial force and shearing force of the bolts to the shear strength of the joints. The calculated results of the shear strength of the anchoring joint surfaces considering the equivalent shearing area are in good agreement with the experimental ones. The greater the inclination of the bolts and the strength of the surrounding rock, the smaller the axial force of the bolts but the greater the shear force. The axial force and shear force of the bolts will increase with the increase of the diameter of the bolts. The normal stress of the joint surface will significantly affect the dilatancy effect, and the greater the normal stress, the higher the shear strength of the joint.