Calculation of pre-stress cable transference of load and effect of anchor

Based on shear displacement method,considering the damage characteristic of rock mass,the nonlinear distribution calculation formula of lateral friction along the anchorage length was deduced.Combining this formula with Mindlin solution,the analytic solution of stress distribution in anchoring rock mass was deduced.Taking advantage of this analytical solution,the specific examples were calculated and analyzed.The results show that the anchor section's stress distribution mainly concentrates in the front end 1/3 of cable,and it is more centralized than the classical approach.Instead of increasing the length of anchoring cable,increasing the anchoring area or dispersing the front end centralized stress can enhance the anchoring effect.In anchor cable's design variable,the neighboring anchor cable mutual influence's minimum range should take the normal stress as a standard to control,but the anchorage force should take the shearing stress as a standard to control.With the increase of cable tensile force,in the anchor section,the range of influence of stress increases less than stress concentration degree.Therefore,the interface's bond strength between anchoring mass and rock mass should be considered much than that between anchoring mass and cable in designing a cable.