基于围岩变形的预应力锚杆受力特征分析及锚固机理

Stress Characteristics Analysis and Anchorage Mechanism of Pre-stressed Anchors Based on Surrounding Rock Deformation

在实际围岩变形条件下对预应力锚杆应力分布进行分析,建立了预应力锚杆-围岩相互作用模型,得到预应力锚杆轴力、剪应力分布解析式,进而获得锚杆应力分布曲线。结果表明:影响锚杆轴力、剪应力分布的因素有预紧力、围岩性质、锚杆及锚固剂参数;在未发生滑移的情况下,自由段所受轴力为定值,锚固段所受轴力沿锚杆长度方向减小至0;而锚杆自由段所受剪应力几乎为0,在锚固段始端剪应力急剧增大至最大值再沿锚杆长度方向衰减至0;在发生滑移的情况下,需对锚固段轴力进行修正,得到锚杆应力分布规律。

The stress distribution of pre-stressed anchors is analyzed under actual surrounding rock deformation conditions.The pre-stressed anchor-surrounding rock interaction model is established,and the axial and shear stress distributions of pre-stressed anchors are obtained,and the stress distribution of anchors is obtained.The results show that the factors affecting the axial force and shear stress distribution of the anchor are pre-tightening force,surrounding rock properties,anchor and anchoring agent parameters;in the absence of slip,the axial force of the free section is fixed,the axial force of the segment decreases to zero along the length of the anchor;while the shear stress of the free section of the anchor is almost zero,the shear stress at the beginning of the anchorage increases sharply to the maximum and then decays to zero along the length of the anchor.In the case of slippage,the axial force of the anchoring section needs to be corrected to obtain the stress distribution law of the anchor.