煤层巷道锚杆索支护性能关键影响因素研究

锚固力与预紧力是实现煤矿井下锚杆索高预应力强力支护的前提,是影响其支护效果的关键因素。为最大限度地发挥锚杆索主动支护性能,以柴家沟煤矿为试验地点,进行锚杆索可锚性试验,锚杆预紧力矩转化效率试验和锚索张拉预紧力损失试验。试验结果表明:柴家沟煤矿巷道已安装锚杆索,在进行拉拔试验时,均能达到足够高的锚固力,锚杆拉拔力为150 k N,锚索拉拔力为200 k N时,锚杆索均未发生失效现象,锚固效果良好;当扭矩为400 N·m时,锚杆预紧力约为43~83 k N,围岩较硬时锚杆预紧力较高,围岩表面松软不完整时,锚杆预紧力偏低;泵压-拉力转化系数较低,锚索张拉时,为保证足够的预紧力,应采取超张拉措施。

Study on Key Influential Factors of Cable Bolting Support Performance in Coal Roadway

The anchoring force and pretightening force are the prerequisite to realize the high prestressed anchor support in the underground mine,and the key factor effecting support.To maximize the active support performance of the anchor cable,taking Chaijiagou Colliery as the test site,anchor cable anchorage test are carried out,and experiment on bolt pretension torque conversion efficiency and prestress loss of cable tension is also taken.The results show that:anchor cable has been installed in the roadway of Chaijiagou Colliery,a high enough anchor force can achieve in the pull-out test,when the anchor pullout force is 150 kN and the anchor cable pullout force is 200 kN,the anchor rods are free from failure phenomena and the anchoring effect is good;when the torque is 400 N·m,the bolt pretightening force is about 43~83 kN,when the rock is hard,the bolt pretightening force is high,when the surface of the surrounding rock is soft and incomplete,the pretightening force is low;when the anchor cable is tensioned,in order to ensure sufficient preload,the super-tensioning measures should be taken when the pump-tension conversion coefficient is low.