The role of hollow bolts in social practice activities. In the layered rock layer, the hollow bolts suspend the unstable rock layer below and the stable rock layer above. The tensile strength of the hollow bolt comes from the suspended rock layer.

　　This kind of sliding friction can prevent the rock layer from dragging along the layer again, thereby clamping several thin rock layers through the hollow bolt into a slightly thicker rock layer. The earth stress and judgment in such thick rock beams are inversely proportional to the thickness of the beam. The thicker the integrated rock beam, the smaller the earth stress and judgment.

　　In addition, the tensile strength of the hollow anchor rod itself also improves the overall bending strength of the beam. Hollow bolts constitute the basic concept of arches. When the hollow bolts of mechanical equipment and steel reinforcement in the cracked area of ​​the soft rock of the coal roadway are provided, the compressive stress field distributed in the form of cones will be formed on both sides of the rod.

　　This supply can accept the radial load released by the broken rock layer above it. The pre-tightening force along the axial direction of the hollow anchor rod causes a stress field in the axillary angle in the constituent arch, thereby significantly improving the stress field condition of the bearing arch, and changing the condition of the soft rock from two shafts and two shafts to three bearing forces. In that way, a continuous bearing area with an average tightening is formed in the soft rock, so that the load capacity of the arch can be greatly developed.