锚杆支护组合构件对钢筋网加固作用试验研究

针对深井高地应力巷道因围岩大变形导致金属网严重破坏引发支护失效的问题,对高地应力巷道支护常用的钢筋网配合单体锚杆、钢筋托梁、W型钢带3种组合系统在垂直载荷作用下的力学性能进行实验室测试,分析了锚杆支护组合构件对钢筋网支护系统峰值强度、承载刚度、残余强度及卸压程度的影响规律,得到了锚杆支护组合构件对钢筋网支护效应的加固特征。借助Ansys Workbench软件分析钢筋网支护系统在垂直载荷作用下的整体位移变形量,得到了锚杆支护组合构件对钢筋网横向、纵向股线的位移约束差异性。基于锚杆支护组合构件对钢筋网的不对称加固特征及边界网丝概念的提出,探讨了锚杆支护组合构件对钢筋网支护系统的加固机理。结果表明:①钢筋网支护系统在垂直载荷作用下的承载性能可分为峰前承载区与峰后卸压区,W型钢带对钢筋网支护系统的强度强化作用是钢筋托梁的1.5倍,刚度强化作用是钢筋托梁的3倍。②锚杆支护组合构件对钢筋网的横向股线加固作用大于纵向股线加固作用,横向股线抗变形阻力分为垂直和水平两个分量,垂直分量由边界网丝与锚杆支护组合构件提供,水平阻力大小取决于边界网丝及焊接点剪切强度。③锚杆支护组合构件通过提高垂直约束作用、护表面积及护表区域内系统的抗变形能力增加钢筋网的支护强度与刚度。

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 constraint 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.