| The weak coal and rock roadway has the disadvantages of low strength,instability and easy deformation,so the bolt support and anchoring effect in the soft rock roadway is not good.The anchoring force of the weak coal and rock mass bolt support mainly depends on the force between the hole wall and the anchoring agent.It is easy to lose the anchor and become unstable,and the residual anchoring force will be greatly reduced.By changing the anchor rod anchor end shape of hole wall effect on the anchoring force is analyzed,and the binary function relationship curve between different parameters L, of the anchoring section of the anchor hole wall shape and the bolt pulling force is established,and it is concluded that anchoring with different hole wall shapes can Effectively increase the anchoring force of the bolt.Using Abaqus finite element analysis software for numerical simulation analysis,based on the stress distribution characteristics of the surrounding rock and anchoring agent of the borehole,it is determined that the angle of the anchoring section of the borehole wall shape is 15°～20°and the length is 50 mm,which can play the best role.work effect.It is proved that the method of changing the shape of the hole wall of the anchoring end of the bolt and adopting multi-segment anchoring is an effective way to improve the anchoring force.By designing the prefabricated hole shape by ourselves,the similar simulation bolt pulling test was carried out on the anchoring of different hole wall forms at the anchoring end of the bolt and the normal anchoring.,and the decay rate of the pull-out force of the anchor rod slows down after the anchoring occurs,which verifies that changing the surface morphology of the anchoring end hole wall of the anchor rod for anchoring can effectively improve the anchoring force of the anchoring system.The research results have important reference value for improving the bolt support of soft rock roadway. |
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