矿用锚索预紧效应分析及锁定计算

预紧力是影响锚固效能发挥的重要指标，为查明其关键作用与锚索张拉锁定的预紧机制，以ANSYS软件模拟方法，探讨了锚索预紧力高低对于锚固串群效应的影响机制，对比了张拉力与预紧力的区别与联系，通过构建拉簧串联模型，推导了锚索由张拉至锁定过程中各元件的受力变形，得出了预紧力形成的计算公式并给出了具体算例。研究表明：持压力越大、围岩越软、自由段长度越长、夹片跟进性能越好，预紧力越高，张拉力损失也越小。工程应用中应兼顾高预紧力的锁定形成及长期保持，综合采取超张拉、补偿张拉、优化自由段长度、匹配限位距离和改进限位方式、锚索注脂等措施，从而全面发挥锚索的支护性能。

Pre-tightening effect of mine cable and its force calculation

The pre-tightening force is a key index in bolting and anchoring engineering,because of its important influence on surrounding rock structures’ rigidity and anchorage group effect.The mechanism using ANSYS simulation and the cable’s pre-tightening course with mechanical analysis was investigated.According to its installation and pre-tighten process,a series drag springs model was put forward for mechanical analysis,which includes surrounding rock,cable,anchor cup,and anchor wedge.The difference and connection of installing tension load and pre-tightening force were analyzed in detail.Some formulas for pre-tightening force were deduced and demonstrated by a calculation example.The studies show that the bigger installing tension load,the softer rock,the longer free cable section and the better following performance of wedges,would lead to the bigger pre-tightening force and the smaller converting loss rate.In the engineering application,the super-tension,replenish-tension,optimal length of free section,improved restriction mode and lag resin bolt,could be applied to realize high pre-tightening force anchoring and better support efficiency.