Mechanical characteristics and engineering application of prestressed full-length grouting anchor cable

In order to study the advantages of prestressed full-length grouting anchor cable compared with end anchor cable in surrounding rock reinforcement, the distribution characteristics of axial force and shear stress of anchor cable were analyzed based on the neutral point theory;the mechanical model of the full-length grouting prestressed anchor cable was established to deduce the analytical solution of the surface displacement of any point of the surrounding rock of the roadway under elastic, elasto-plastic and plastic states;the control effect of prestressed full-length grouting anchor cable on the radial and tangential deformation of surrounding rock was studied. Taking 9# connecting lane of No.33042 lane in a coal mine of Jinmei Group as the engineering background, the support effect of conventional anchor cable and prestressed full-length grouting anchor cable without and under the influence of mining was analyzed. The research results show that the deformation of surrounding rock near the roadway surface is greater than that of anchor cable, and the shear stress on the surface of the anchor body points to the roadway free surface. In the deep part of surrounding rock, the deformation of surrounding rock is less than that of anchor cable, and the shear stress of anchor solid points to the deep part of surrounding rock, and the shear stress of both sides is opposite. Axial tension of anchor solid shows curve distribution, and it is the largest at the neutral point;under the influence of mining, the deformation trend of ordinary anchor cable and prestressed full-length grouting anchor cable support roadway is the same. The deformation of the roadway is severe at the beginning of excavation, and then tends to be gentle. The stress full-length grouting anchor cable can reduce the approaching amount of the roof and floor by 50%;during the mining impact period, under the support of the pre-stressed full-length grouting anchor cable, the approaching amount of the roof and bottom plate and the two sides are reduced by 21.1% and 22.1% respectively, the stress of anchor cable is generally increased, and the change is small, and there is no anchor cable breaking phenomenon;compared with the end anchor, the prestressed full-length grouting anchor cable has obvious advantages in the control of the radial and tangential deformation of surrounding rock, and it can solve the problem of anchor cable breaking caused by the shear action of composite roof roadway.