不同边界约束对锚杆锚固段承载特征影响试验  

Experimental on the influence of different constraint conditions on the bearing characteristics of rock bolt

作　　者：李怀珍[1] 贺炫 龙丽群 范道鹏 LI Huaizhen;HE Xuan;LONG Liqun;FAN Daopeng(College of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China)

机构地区：[1]河南理工大学安全科学与工程学院,河南焦作454000

出　　处：《采矿与岩层控制工程学报》2022年第3期24-33,共10页Journal of Mining and Strata Control Engineering

基　　金：河南省科技攻关资助项目(212102210230);河南理工大学青年探索基金资助项目(NSFRF210306);河南理工大学博士基金资助项目(B2020-5)。

摘　　要：为研究不同边界约束对锚杆锚固段承载特征的影响,在分析巷道围岩锚杆张拉预紧与协调变形时段承载状态的基础上,利用专用张拉试验台,开展不同边界约束锚固试件轴向加载试验。研究结果表明:①硬质围岩、环氧植筋胶粘结锚固体锚杆抗拔能力和锚杆-锚固剂界面剪应力较大;②不同边界约束锚固单元体锚固失效模式主要有4种:锚固剂破碎、以锚孔为中心出现辐射状裂纹、锚固基体崩解、锚固基体出现轴向贯通裂纹导致锚杆滑脱;③不同边界约束锚固试件锚杆轴力沿锚固长度均呈递减规律,有侧向约束锚固试件锚杆轴力递减速度大于无侧向约束试件;④不同边界约束条件下锚杆-锚固剂界面剪应力分布规律和峰值位置差别明显,锚杆在张拉预紧和锚杆-围岩协调变形的不同时段需采取不同锚固失效防范措施。In order to study the influence of different boundary constraints on the bearing characteristics of the anchorage section,a special tension test bench was fabricated based on the analysis of the bearing state of the anchoring unit in the two periods of pretensioning and coordinated deformation.The axial loading tests of the specimens under different boundary constraints were carried out.The results show that:①Under the condition of hard surrounding rock and epoxy bonding,the pullout capacity of the bolt and the shear stress at the interface between the bolt and anchorage are large;②The failure modes of anchoring elements with different boundary constraints can be divided into four types:breakage of anchorage,radial crack centered on the borehole,specimen disintegration,axial crack penetration,and bolt slippage;③The axial force of the bolt with different boundary constraints decreases along the anchorage length,and the decreasing speed of the axial force of the bolt with lateral constraints is faster than that of the bolt without lateral constraints;④Under different boundary constraints,the distribution law and peak position of shear stress at the interface between bolt and anchorage agent is different.In different periods of bolt preloading installation and bolt-surrounding rock coordinated deformation,different anchorage failure prevention measures need to be taken.

关 键 词：煤巷锚杆 边界约束 张拉试验 承载特征 

分 类 号：TD353[矿业工程—矿井建设]