巷道围岩锚固结构面剪切特性与破坏特征研究

Study on shear properties and failure characteristics of bolted joint of roadway surrounding rock

为研究锚固巷道围岩结构面的剪切特性与破坏特征,采用FLAC_(3D)软件建立粗糙锚固结构面数值模型开展剪切试验,对锚固系统的剪切特性以及受力变形和破坏特征进行了系统研究。结果表明:锚杆能够有效提高结构面的抗剪能力,锚固系统的剪切应力在峰值位移处提升了0.33 MPa,在剪切结束时提升了0.93 MPa。锚杆所受剪切应力集中在结构面附近,锚杆所受的轴力在结构面两侧呈两组对称分布的压应力区和拉应力区。锚杆在结构面处的剪切应变较大,拉应变次之。锚固剂-围岩界面和锚杆-锚固剂界面的剪切应力在结构面处最大,锚杆-锚固剂界面所受剪切应力和受力范围更大。塑性破坏主要产生在锚杆与结构面相交处和结构面凸起处,锚固剂多是发生拉伸破坏,围岩则多是发生剪切破坏。锚杆-锚固剂界面更容易发生脱离,导致锚固系统失效。

To study the shear properties and failure characteristics of the bolted joint of roadway surrounding rock,a numerical model of the rough bolted joint was established by using FLAC_(3D) software to conduct shear tests.The shear properties and the force deformation and failure characteristics of the anchoring system were systematically studied.The results show that the bolt can effectively improve the shear capacity of the structural face,and the shear stress of the anchoring system is increased by 0.33 MPa at the peak displacement and 0.93 MPa at the end of shear.The shear stress of the bolt is concentrated near the joint,and the axial force of the bolt is symmetrically distributed in two groups of compressive and tensile stress zones on both sides of the joint.The shear strain of the bolt at the joint is relatively large and the tensile strain is relatively small.The shear stresses at the anchoring agent-rock interface and the bolt-anchoring agent interface are greatest at the joint,and the shear stresses and force range at the bolt-anchoring agent interface are greater.Plastic failure occurs mainly at the intersection of bolt and joint and at the projection of joint.Tensile failure occurs at the anchoring-agent and shear failure occurs at the surrounding rock.The bolt-anchoring agent interface is more prone to detachment,resulting in anchoring system failure.