煤巷锚杆树脂锚固体空洞现象及其力学特性

Bonding empty in epoxy bonded section of bolt in coal roadway is influence the supporting effect and roof safety obviously. In this topic, firtly, the data of bolt stress in epoxy bonded anchor system will be gathered through FBG dynamic real-time monitoring system for bolt in coal roadway, then the bonding empty phenomenon will be proposed and the major factors that induce empty phenomenon will be analyzed. Combined with the nondestructive measurement and laboratory simulation results，the distribution and evolution of stress in bolt will be presented. Sencondly, a theoretical model of resin bonded anchor system with empty in bonding adhesive layer will put forward based on the visco-elastical and interface shear slip theory, the formulas of axial stress in the blot and the shear stress at the bolt-epoxy interface along the embedded direction and the ultimate bearing will been obtained, the distribution and evolution of bolt stress in this anchor system will be developed combining with the results of simulation,field measurement and laboratory research, some primary parameters will also be conducted to demonstrate their effects on this anchor system. Simultaneously, a simple method to fix the empty location in anchor system will be put forward。Finally, targeted measures will be raised to prevent the empty anchor failure. This research results will enhance the bolt support reliability and further encourage the bolt supporting technology and surrounding rock control theory.

煤巷锚杆树脂锚固段的空洞现象影响锚杆支护效能及顶板安全。课题采用光纤光栅煤矿巷道锚杆应力动态实时在线监测系统采集巷道开挖至围岩稳定过程中锚杆应力及其变化数据，描述树脂锚固体锚固空洞现象，并分析诱发空洞产生的主要因素；结合锚杆锚固质量无损实测和实验室相似材料模拟结果，研究不同锚固形式下锚杆应力分布及演化特征；基于弹塑性和粘结界面剪切滑移理论建立空洞树脂锚固体力学模型，具体推导拉拔状态下杆体内应力分布函数和杆体极限承载表达式，借助数值模拟进一步分析空洞树脂锚固体应力分布及其演化特征，确定影响此类锚固体力学性能的主要因素，系统揭示空洞树脂锚固体的力学行为特性；同时提出一种简便定位锚固体空洞位置的方法及防治措施，以提高锚杆支护可靠性及支护效能，进一步完善和发展锚杆支护技术和巷道围岩安全控制理论。

本项目研究确定了制作光纤光栅测力锚杆合理的杆体开槽形状及较理想的光纤光栅粘贴材料，完善了光纤光栅煤矿巷道锚杆应力动态实时在线监测系统并完成光纤光栅测力锚杆井下安装。基于实验室试验、井下拉拔试验及锚杆受力实时监测试验结果，综合分析了锚杆杆体应力分布及传递演化特征。研究表明在理想锚固状态下，沿锚固方向锚杆杆体内应力分布呈现先增大后减小的特征，外锚固段是锚杆限制巷道围岩变形的主要承载区，研究发现锚杆杆体内存在大量弯矩其会显著影响锚杆的应力分布及传递，在一定范围内增加预拉力值可以提高锚杆的承载状态发挥其支护效能，同时揭示了煤矿井下实际工作状态下的锚杆杆体受力呈现非均匀分布且波动变化的特征，提出了煤矿树脂锚杆锚固体的失效类型及锚固空洞失效现象。分析了煤矿锚杆的失效类型，具体揭示了煤巷锚杆树脂锚固体的空洞现象并分析了诱发空洞产生的主要因素。基于弹性理论建立空洞树脂锚固体的力学模型，推导出了拉拔状态下杆体内应力分布的函数表达式；同时实验室获取了杆体、围岩及树脂锚固剂的相关物理力学参数，结合数值模拟果揭示此类锚固体锚杆应力分布及演化特征，并分析了影响空洞树脂锚固体力学性能的主要因素，较系统研究了煤巷锚杆空洞树脂锚固体的力学特征。基于理论研究结果，提出定位锚固空洞位置的方法和具体防治此类空洞失效的针对性技术措施。在本项目的资助下，课题组共计发表论文4篇，其中SCI收录2篇，EI收录2篇；申请发明专利5项，获授权3项，同时获授权1项PCT专利。