Development of hyperbolic model for fully grouting rock bolt and parameters analysis for anchoring effect

According to local deformation theory, taking the action of rock mass against grouting rock bolt as a serious of spring, the shear resistance increases linearly with shear displacement between grouting mass and surrounding rock, and the hyperbolic model for grouting rock bolt has been developed on the base of rock bolt's force equilibrium. The distribution of shear resistance, axial force and shear stress density along the grouting rock bolt is obtained. From the shear stress and axial force of grouting rock bolt, the parameters affecting the anchoring effect have been analyzed. It is concluded that the larger the radial of rock bolt is, the greater the anchoring effect is; the greater the elastic modulus of rock bolt is, the better the anchoring effect is; and as the comprehensive parameter of grouting mass and surrounding rock increasing, the anchoring effect becomes better.