Experimental study on mechanical properties and force transfer mechanism of bolt supported metal mesh

In view of the common failure modes of strength and stiffness of underground metal mesh seriously restrict the safety and reliability of roadway,the self-developed metal mesh static load test system is used to test the three types of metal mesh,and the support strength,stiffness and deformation failure mode of three types of metal mesh under vertical load are obtained;the three types of metal mesh are obtained with the help of finite element analysis software According to the mechanical response characteristics,stress distribution law and force transmission mechanism of the three types of metal mesh,the structural optimization suggestions are given. The results show that:① The load displacement curve of metal mesh support system under vertical load can be divided into three parts:load transfer stage,mesh deformation stage and structure failure stage. ② The results show that the reinforcement mesh has the characteristics of high stiffness support,and the rhombic mesh has the characteristics of high strength support. The mesh dislocation of the warp and weft mesh under the vertical load is an important reason to reduce the support strength and stiffness. ③ The mesh wire in the central cross\" shaped area of the reinforcement mesh and the warp and weft mesh bears the axial stress in the central X\" shaped area. ④ During the loading process,the steel mesh support system presents the central ten\" type force transmission mode,the diamond mesh support system presents the center X\" type force transmission mode,and the warp and weft mesh wire slides from the high stress area to the low stress area under the external load. ⑤ The boundary wire,which directly determines the supporting effect of metal mesh,is subject to shear and torsion in vertical and horizontal directions respectively,and the strength of binding wire has great influence on the horizontal twisting effect of boundary wire. ⑥ Whether the three kinds of metal mesh can be effectively supported or not,we should focus on the problem of force transmission mechanism to carry out local wire binding reinforcement,node constrained anti-skid and optimization of row spacing between supporting bolts.