煤岩锚固系统滑移脱黏试验研究与力学性能分析

Experimental research on slippage mode and analysis on mechanical properties of coal rock anchorage system

为得到不同锚固长度煤岩锚固系统失效模式与力学性能,结合煤巷树脂黏结锚杆锚固特点,在配比出中等硬度煤岩体相似材料基础上,按照工程现场操作流程制作不同锚固长度、树脂黏结中硬煤岩锚固体,开展了室内拉拔试验。研究结果表明:锚杆载荷-位移曲线可分为弹性变形阶段、塑性变形阶段、脱黏延伸阶段和完全脱黏阶段。拉拔荷载作用下,中硬煤岩锚固体失效模式主要为煤岩体与锚固剂界面间的滑移脱黏失效。随着锚固长度增加,锚杆最大抗拔力不断增加,塑性变形阶段锚杆最大抗拔力是弹性极限抗拔力的1.21~1.34倍;弹性变形阶段,锚杆轴力自锚固起始端迅速下降直至锚固尾端很小。通过张拉试验测得锚固剂与煤岩体界面剪切刚度大致为259.8~272.5 MPa/m,抗剪强度大致为1.22~1.57 MPa,为锚固系统失效模式判识和支护设计提供指导。

To obtain the failure mode and mechanical properties of coal rock anchoring system bonded through resin, the medium hardness material has been prepared by the similar simulation experiment and anchor solids of different lengths have been made which refers to the practices of coal mine. Through indoor pull-out test, the paper found that the load-displacement curve can be divided into four stages： elastic deformation stage, plastic deformation stage, debonding extension stage, complete de-bonding stage. Under the action of drawing, the failure location of anchoring body is mainly interface between coal and capsule resin. The maximum pull-out force of bolt increases as the anchoring length increases, the maximum pull-out force of plastic deformation stage is 1.21-1.34 times of the value of elastic deformation stage. In the elastic deformation stage, the axial force of anchor bolt descends ra-pidly along length direction. The shear stiffness of interface between capsule resin and coal is about 259.8-272.5 MPa/m and the shear strength is about 1.22-1.57 MPa. Research findings can help to predict the failure mode of anchorage system, and also can provide guidelines for support design.