Development of a Device for Evaluation of Resin Bolt Installations

摘要

This report describes the development of a device for nondestructive testing of resin-grouted roof bolts by mechanical frequency response. Various alternative methods were evaluated and the mechanical frequency response method was selected. An interactive program of design, testing, and development culminating in the current prototype instrument demonstrated the capabilities of the method and suggested potential applications. The resin bolt testing device utilizes a swept frequency dynamic compliance measurement in the 1 to 2 kHz range that is interpreted by an electronic signal processor to give a 'GO' or 'NO GO' readout. Field tests showed that the device can reliably determine the bond quality of the front half of the bolt (nearest the roof surface). Tests were carried out on both experimentally installed bolts and typical mine bolts installed by a conventional bolting machine. The program has led to recommendations for improvement of the prototype and future development work.