Experimental study on reinforcement effect of bolt support composite members on reinforced mesh

In view of the failure of metal mesh caused by the large deformation of surrounding rock in the high stress roadway of deep mine,the mechanical performance of the three combined systems,i. e. welded mesh,single bolt,steel joist and W steel strip,which are commonly used in the high stress roadway support,is tested in the laboratory under the vertical load,and the peak value of the combined components of bolt support to the welded mesh support system is analyzed. The law of the influence of the peak-value strength,bearing stiffness,residual strength and the degree of pressure relief is obtained. With the help of ANSYS Workbench software,the displacement and deformation of the whole welded mesh support system under the vertical load are analyzed,and the difference of the displacement con- straint of the combined components for bolt support on the transverse and longitudinal strands of the welded mesh is obtained. Based on the concept of boundary mesh wire and the asymmetric reinforcement characteristics of bolt support composite members to welded mesh,the reinforcement mechanism of bolt support composite members to welded mesh support system is discussed. The results show that ① the bearing capacity of the welded mesh support system under the vertical load can be divided into pre-peak bearing area and post-peak pressure relief area. The strength strengthening effect of W steel strip on the welded mesh support system is 1. 5 times of that of the steel joist, and the rigidity strengthening effect is 3 times of that of the steel joist. ② The transverse strand reinforcement effect of the bolt support composite component is greater than that of the longitudinal strand reinforcement. The transverse strand resistance to deformation is divided into vertical and horizontal components. The vertical component is provided by the boundary mesh wire and the bolt support composite component. The horizontal resistance depends on the boundary mesh wire and the shear strength of the welding point. ③ The strength and rigidity of the welded mesh support are increased by increasing the vertical restraint,the surface area and the anti-deformation ability of the system in the surface area.