一种新型倒刺锚杆创新研究

Innovative Research on a New Type of Barbed Anchor

摘要: 创新发明了一种新型的倒刺锚杆，由母体锚杆和子体倒刺构成，母体锚杆一般采用HRB400或HRB500粗钢筋，子体倒刺为四周带有外扩薄片如倒刺的中空结构，可以通过内置螺纹和母体锚杆螺纹连接固定，也可通过焊接和母体螺杆连接。子体倒刺沿母体锚杆成一定间距布设。成孔后锚杆放入时，倒刺结构的外扩薄片在孔壁约束下，呈微收缩状态紧贴孔壁滑动，到达预定位置后，锚杆在向外拉力作用下，由于孔壁表面呈凹凸糙面，倒刺外扩薄片会顶住孔壁，如果孔壁为硬质岩石，外扩薄片和孔壁之间则为硬接触关系，如果孔壁为软质岩石或土质，外扩薄片则会刺入孔壁，扩大作用范围，提高承载力。基于ABAQUS数值计算软件，研究了倒刺锚杆在硬质岩壁中的力学行为，研究表明：由于倒刺的存在，提高了锚杆的抗拔承载能力，当孔壁为硬质岩石时，外扩薄片和孔壁之间则为硬接触关系，不考虑灌注水泥浆体，倒刺锚杆的抗拔力可达数吨；如果考虑注浆体，倒刺锚杆的抗拔能力会大幅提高，可达几十吨。同时倒刺锚杆制作简便、倒刺结构兼具锚杆对中支架的作用，很有应用发展前景。不足之处在于倒刺锚杆由于倒刺直接和孔壁接触，在作为永久锚杆时，一般只能用于无腐蚀或微腐蚀环境，不宜应用于腐蚀的环境。

Abstract: A new type of barbed anchor is innovated and invented, which is composed of parent anchor and daughter barbed anchor. The parent anchor generally adopts HRB400 or HRB500 thick steel bar. The daughter barbed anchor is a hollow structure with external expansion sheet, such as barb. It can be fixed by internal thread and parent anchor thread connection, and can also be connected with parent screw through welding. The daughter barbs are arranged at a certain distance along the parent anchor. When the anchor is put into the hole after hole forming, the outward expanded sheet of the barbed structure slides close to the hole wall in a micro contraction state under the constraint of the hole wall. After reaching the predetermined position, the barbed outward expanded sheet will support the hole wall due to the concave convex rough surface of the hole wall under the action of outward tension. If the hole wall is hard rock, the relationship between the expanded thin section and the hole wall is hard, and if the hole wall is soft rock Stone or soil, the expansion of thin sections will pierce into the hole wall, further expand the scope of action. Based on ABAQUS numerical calculation software, the mechanical behavior of barbed anchor in hard rock wall is studied, and the results show that: because of the existence of barb, the uplift bearing capacity of the anchor rod is improved. When the hole wall is hard rock, the relationship between the expanded thin plate and the hole wall is hard contact. If the grouting body is considered, the pull-out capacity of the barbed bolt can reach several tons; if the grouting body is considered, the pull-out capacity of the barbed bolt will be greatly improved, up to dozens of tons. At the same time, the barbed anchor is easy to make and the barbed structure has the function of anchor centering support, so it has a good application prospect. The disadvantage is that the barbed anchor is in direct contact with the hole wall. As a permanent anchor, it can only be used in non corrosive or micro corrosive environment, not suitable for corrosive environment.