Abstract：In the pullout test of the peak shear strength between the grout and the bore wall in the interior bond section of prestressed anchor cable，it is observed that the specimen is instantly cracked by the hoop tension which is result of the geometric wave shape of borehole wall when the specimen is subjected to axial tension. The reason of this phenomenon is analyzed；and it is pointed out that the geometric wave shape of borehole wall，the tiny change in aperture of borehole，and the tortuous axis of cable are the main reasons of the phenomena. The geometric wave shapes of borehole wall in granite，gritstone and limestone are measured and presented. The effects of the geometric wave shape of anchor cable borehole wall on the bearing capacity of anchor cable are analyzed. Finally，it is found that the remote change in aperture of borehole，and the tortuous axis of cable have greater effects on numerical calculation. Because the effect is very obvious，it should be taken into account in anchoring project.
