针对目前井下普遍存在的锚杆杆尾预紧扭矩向预紧力转化效率低的问题,理论分析了预紧扭矩与预紧力之间的关系,建立了数学表达式,分析了锚杆杆尾预紧扭矩转化效率低的主要影响因素。利用锚杆预紧扭矩试验台,试验研究了锚杆杆尾螺纹加工精度、锚杆螺纹处直径及减磨垫片材质3种因素对杆尾预紧扭矩转化效率的影响,得出了螺纹加工精度、锚杆螺纹处直径及减磨垫片材质与锚杆杆尾预紧扭矩转化效率之间的关系,并通过井下试验加以验证。研究结果表明:提高杆尾螺纹加工精度,减小锚杆螺纹直径,使用合适的减摩垫片均能提高杆尾螺纹预紧扭矩向预紧力转化的效率,但减磨垫圈对其影响最显著。井下试验结果与试验室试验结果基本相符,进一步说明了螺纹加工精度、锚杆螺纹处直径及减磨垫片材质对锚杆杆尾预紧扭矩转化效率的影响。
In view of the low conversion efficiency between pre-tightening torque and pre-tightening force, theoretical analysis of the relationship between the pre-tightening force and the pre-tightening torque were conducted and mathematical expression was established. Meanwhile, the main influence factors of the low conversion efficiency were analyzed in anchor rod end pre-tightening torque. Three influence factors for anchor rod end thread machining precision, anchor diameter and antifriction gas- kets material on rod end pre-tightening torque conversion efficiency were studied through bolt pre-tightening torque test system, and the impact of three factors on the pre-tightening torque conver- sion efficiency of thread end of rock bolts was obtained and also verified by field tests. The results have indicated that improving the rod end thread machining accuracy, reducing the bolt diameter of thread, and applying the appropriate antifriction gaskets all can improve the rod end thread pre-tightening torque to the conversion efficiency of the pre-stressing force. By contrast, antifriction gaskets material is the most significant influence factor. Test results were consistent with the results of laboratory tests,thread machining precision, anchor diameter and antifriction gasket material on the influence of the an- chor rod end pre-tightening torque conversion efficiency was further explained.