Experimental Study On Deformation Characteristics Of Metal Net In Anchor-net Supporting Roadway

In order to explore the mechanical deformation and destruction of metal net in bolt- net supporting under the action of upper broken rock,to provide a basis for the use of metal net in bolt- net supporting. This paper made the theoretical analysis and laboratory tests of the metal net in bolt- net supporting.Combined with the condition of broken surrounding rocks under bolt-net supporting in compressive arch theory of bolt, analysis of the load distribution of metal net. Establish the mechanical model, do theoretical derivation and analysis to metal net subsidence. Finally found the net center net deformation curve can be described by one basic three equation. Increasing the anchor spacing and rock density can increase the metal net subsidence, while increasing the rock internal friction angle and bold the mesh can reduce the metal net subsidence.Design and process special metal net indoor loading device, do laboratory loading on warp-weft welding net and rhombic net which are commonly used in coal mine bolt-net supporting. Observe and record the deformation and destruction of warp-weft welding net and rhombic net in different mesh size, different mesh diameter, double network, as well as different bolt row, while loading. Find the surface protection rigidity and timeliness of warp-weft welding net welded net is superior to rhombic mesh. The allowable deformation of rhombic net is significantly higher than that of warp-weft welded net, the surface protection flexibility is superior to warp-weft welding net. And the rhombic net can provide higher maximum surface protection force than the warp-weft welded net. Reducing the mesh size, bold the mesh, use double layer network can effectively increase the surface protection rigidity and timeliness of metal net. Increasing row spacing can obviously reduce surface protection rigidity of metal net. Increasing row spacing and reducing mesh size can reduce the metal net maximum surface protection force, while bold the mesh, use double layer network can increase the metal net maximum surface protection force. Before breaking of warp-weft welded net, the strain distribution is reduced gradually from the edge to the center of the net.