张拉预紧式锚杆支护系统高能强化锚固机理研究

目前传统转矩式锚杆预紧力损失大、锚杆主动性利用率较低,难以满足深部复杂困难巷道的支护要求,因此提出了张拉式高预紧锚杆支护技术,开发了张拉预紧式锚杆锁具及相关构件,并对系统在实验室进行了锚杆拉伸试验,结果表明:在锚具锥度为6°时,整个锚杆拉伸过程直至锚杆破断后锁具都可实现自锁,锚杆破断时,锁具总后退距离平均为3.3 mm,验证了锁具系统的安全性、匹配性及稳定性。而后采用数值模拟的方法建立了巷道锚固分离体模型,对比了低、高预紧力下锚固体的变形破坏特征与能量演化机制,最终得出高预紧力锚杆比低预紧力锚杆更能提高锚固体强度,减小锚固体受载变形的破坏程度,高预紧力产生的高储能可有效提高锚固体破坏峰值,减小破坏时的总耗散能,有效提高锚固体峰后残余能量。基于理论分析结果,在王庄煤矿91采区运输大巷进行了张拉预紧式锚杆与普通转矩式锚杆的对比试验,据矿压监测结果显示采用张拉预紧式锚杆的巷道段两帮最大移近量减少了32.6%,证明了提高预紧力构建高储能锚固支护体系可以有效减小巷道变形。

Study on high-energy strengthening anchor mechanism of tension pre-tightening bolt support system

At present,traditional torque anchor bolts have large loss of preload and low utilization rate of bolts,which is difficult to meet the support requirements of deep complex and difficult roadways.Therefore,the tension pre-tightening bolt support technology is pro?posed,the tension pre-tightening bolt lock and related components are developed,and the system has been subjected to a laboratory an?chor rod tensile test.The results show that when the anchor taper is 6°,the bolt is locked after the bolt is broken during the whole stretc?hing process.When the anchor rod is broken,the total distance of the lock system is 3.3 mm on average,which verifies the safety,matc?hing and stability of the lock system.A numerical simulation method was used to establish a roadway anchorage separation model,and the deformation and failure characteristics and energy storage mechanismof the anchorunder high and low preload anchor were compared.Final?ly,it was concluded thatthe high preload bolt was compared with the low preload bolt and the high preload bolt can improve the strength of the anchor body and reduce the damage degree of the anchor body under load.The high energy storage achieved by the high preload can ef?fectively improve the peak value of the anchor body failure and reduce the damage degree of the anchor body The total dissipated energy during failure can effectively improve the residual energy of anchorage body after peak.Based on the results of theoretical analysis,a com?parative test of tensioned pre-tightening bolts and ordinary torque bolts was carried out in the main roadway of rubber-tyred vehicles in No.91 mining area of Wangzhuang Coal Mine.The maximum moving distance of the two sides of the roadway section of the roadway section has been reduced by 32.6%,which proves that the deformation of roadway can be effectively reduced by increasing the preload to construct high energy storage anchor.