管缝式锚杆在拉拔荷载作用下受力分析模型

建立了管缝式锚杆在拉拔荷载作用下的受力分析模型，该模型能够反映锚杆破坏的渐进过程。分析表明，在拉拔荷载作用下管缝式锚杆在荷载作用点最先发生相对滑移，且随着荷载的增加滑移段的长度逐渐增加，直到整根锚杆与围岩发生相对滑移。根据能量守恒原理得到了管缝式锚杆在安装入钻孔后对围岩径向作用力的计算公式。对管缝式锚杆进行了非局部摩擦分析，得到了基于非局部摩擦模型的管缝式锚杆界面剪应力分布。研究了管缝式锚杆直径对锚杆界面剪应力分布的影响，同时得到了锚杆最大抗拉拔力与锚杆长度之间的关系。将理论模型预测值与试验结果对比，验证了理论模型的有效性。

Analytical model for split-set rock bolt under pull-out force

A new analytical model for split-set rock bolt under pull-out force has been developed. Research shows that slips may occur first at the loading point under pull-out force when the applied load is large enough. The length of slip segment increases with an increase in the applied load, and finally the length of slip zone arrives at the length of rock bolt. Based on the conservation of energy, formulae of radial forces acting on the surrounding rock mass induced by split-set rock bolt are obtained. On the basis of nonlocal friction model, the distribution of shear stress on the interface of split-set rock bolt is determined. Through the parametric study of an illustrative case, effects of the rock bolt’s diameter on the distribution of shear stress is studied, the relationship between the ultimate pull-out strength and rock bolt’s length is also obtained. It is shown that the present analytical model is in good agreement with the experiment results.