超高强热处理锚杆开发与实践

我国煤矿锚杆强度偏低，对冲击吸收功没有指标要求。通过对煤矿井下锚杆破断情况调查及分析，发现锚杆破断强度低、夹杂物含量高、冲击韧性不足、抗冲击能力不够是造成杆体脆断的重要原因，冲击韧性值低是发生脆断的材质内在因素。介绍了超高强热处理锚杆的主要工艺，对超高强热处理锚杆材料进行了拉伸、拉扭弯及力学性能实验室试验，数据显示这种材料在受拉、扭、弯的情况下可以承受较高的载荷，特别是冲击吸收功指标，是热轧强力锚杆的数倍。在潞安集团漳村煤矿动压巷道进行了井下现场试验，对超高强热处理锚杆受力情况进行了监测，锚杆施加预紧扭矩后初始预紧力为52~98 kN，受力稳定后最大受力为223 kN，小于其破断极限，矿压监测数据表明，支护系统有效地控制了围岩的变形，支护效果良好。

Development and application of ultrahigh-heat processed rock bolts

In Chinese coal mine industry,most of rock bolts have a low load-bearing capacity and have no requirement for impact absorbing energy.An investigation of broken rock bolts was carried out in underground coal mines and it was found that the major reason of bolt failure was low tensile strength,high inclusion content,lack of impact toughness and impact-bearing capacity.Low impact toughness is the intrinsic reason for bolt broken.To overcome this problem,an ultrahigh-heat processed bolt was developed.The capacity of this type of bolts was evaluated by doing pull-load and twisting tests.The experimental results show that the ultrahigh-heat processed bolts exhibit higher load-bearing capacity comparing to conventional bolts.The coefficient of impact-absorbing energy of the ultrahigh-heat processed bolt is many times higher than that of the conventional bolts.The ultrahigh-heat processed bolts have been used for supporting a roadway subjected to dynamic stresses at Zhangchun Coal Mine in Lu’an.The pre-tension was between 52 to 98 kN and the monitored maximum load was 223 kN which was less than its broken load.The deformation of the roadway was efficiently controlled by the ultrahigh-heat processed bolts.