Axial force detection method based on lateral vibration frequency response characteristics of rock bolt system
The detection method based on the lateral vibration characteristics of the free segment of rock bolt system can quickly and effectively detect rock bolts on a large scale.To improve the accuracy of rock bolts axial force detection,this paper established a lateral vibration mechanical model for the rock bolt system and tested the frequency response of the full-scale rock bolt system during axial loading.The results indicate that the lateral vibration frequency of the rock bolt system is sensitive to the rotational stiffness and the free segment length of rock bolts.By calibrating the rotational stiffness of the theoretical model through experiments,the theoretical results obtained are in good agreement with the experimental results,and the lower the frequency order,the smaller the error in axial force detection.When the axial force is low,the average relative error of the fundamental frequency axial force detection is 5.8％,while when the axial force is high,the average relative error is only 0.6％.When the body of rock bolts enters plastic or interface debonding and sliding,the length of the free segment of the rock bolt changes significantly.By adjusting the length of the free segment of the rock bolt in real time,the axial force detection during the damage stage of the rock bolt system can be achieved,and the average relative error of the fundamental frequency axial force detection is within 4.1％.The rapid and non-destructive testing method of the rock bolt axial force is of great significance for the evaluation of support system and surrounding rock stability.
rock bolt systemnon-destructive testingaxial force of rock boltvibration modelnatural frequency
万方数据
维普
