Abstract: To reveal the pre-stressed anchor mechanism and optimize the supporting parameters of surrounding rock, the stress of the anchor and surrounding rock system was analyzed in this paper, and the expressions of shear and compressive stress distribution in surrounding rock under the elastic state were obtained. By using MATLAB, the pre-stress distributions in the rod body and surrounding rock under different conditions were calculated, such as different anchoring methods, surrounding rock properties, bolt diameters and pre-tightened forces. The results show that, under different anchoring methods, the distribution forms of pre-stresses are basically the same, but the action spheres are different. The lengthening of bolting method can increase the sphere of pre-stress, and the effect of pre-stressed anchor in the soft rock is better than that in hard rock. The increase of anchor diameter can improve the diffusion effect of sticky anchor force in the surrounding rock, while the increase of the pre-tightened force can’t change the pre-stressed diffusion range in anchored section, but can improve its peak stress, and improve the compressive stress of surrounding rock near orifice as well, which has efficient improvement effect of stress state on the surface of surrounding rock.

Key words: anchoring pre-stress, pre-tightened force, anchoring method, influencing factors