Based on probe to the difficulty in the full-scale test-in-situ of the anchor cable
then the stress and displacement of the prestressed anchor body
the distribution principle of the shear stress on anchor body face
which is influenced by the different anchor cable rigidities
the elastic modulus of rock-soil body and the scale of prestressing; and the diversion trend of the plastic damage zone are numerically simulated by use of FLAC3D. The distribution formula of shear stress which has the r index function relationship is fitted. Under the deduction that the peak value of the shear stress continuously expands to the tail of the anchor body
the paper puts forward the formula for ultimate anchor force on the interface of the grouting body and rock-soil; it has academic and practical significance.