横肋对螺纹钢树脂锚杆荷载传递的影响

螺纹钢横肋的外形及尺寸显著影响树脂锚杆的锚固能力。为分析横肋对螺纹钢树脂锚杆荷载传递的影响，将拉拔条件下的螺纹钢树脂锚杆简化为轴对称模型，基于剪切-位移原理导出了关于剪切位移的二阶周期间断变系数齐次微分方程，对周期间断变系数进行Fourier变换，基于MATLAB求解出横肋影响下螺纹钢树脂锚杆剪切应力分布规律，并与圆钢锚杆进行对比分析；采用ABAQUS对螺纹钢锚杆受力进行模拟分析，并与理论分析结果对比验证；提出横肋应力集中因数F，对横肋的影响范围与影响程度进行了分析。研究表明，螺纹钢锚杆剪切应力沿锚杆轴向呈锯齿状递减分布；锚杆有效锚固承载区域内横肋应力集中因数F范围为[1.875，2.156]；300 MPa拉拔荷载条件下横肋附近剪切应力峰值可达36 MPa，预示着锚固系统易从横肋附近损伤破坏。

The effect of rib on load transfer of the thread steel resin bolt

The contour and size of the rib on the thread steel have significant effects on the anchoring strength of resin bolt in the coal mine. To analyse the effects of ribs on load transfer of thread steel bolt, theoretical analysis and numerical simulation methods were used for solving the load distribution of the bolt. By simplifying the mechanical model of the bolt as an axisymmetric model under the pull-out condition, the second-order variable coefficient differential equation has been derived for the shear displacement, in which the variable coefficient function is periodic and discontinuous. Based on MATLAB, this differential equation is solved by Fourier transforming the periodic, discontinuous and variable coefficient function into a continuous function. Thus, the shear stress distribution is obtained and then compares with that of the round steel bolt. Furthermore, a numerical simulation of the bolt has been conducted by ABAQUS to verify the correctness of theoretical solutions. Moreover, based on the results of theoretical analysis and numerical simulation, the rib stress concentration coefficient F is defined to discuss the range and degree influenced by the rib. The results show that the shear stress is a zigzag decreasing distribution along the long axis of the bolt. The rib stress concentration coefficient F is in a range of 1.875 and 2.156 in the effective bearing zone of the bolt. For pull-out force of 300 MPa, the shear stress peak value reaches 36 MPa, which indicates that the initial damage and failure zone commonly occurred near the rib in the anchoring system.