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 proposed,the tension pre-tightening bolt lock and related components are developed, and the system has been subjected to a laboratory anchor 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 stretching process.When the anchor rod is broken, the total distance of the anchor cable is 3.3 mm on average, which verifies the safety, matching 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. Finally, 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 effectively 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 comparative test of tensioned pre-tightening bolts and ordinary torque bolts was carried out in the main roadway of rubber-tyred vehicles in the 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.