MONITORING BEHAVIOR OF GROUTED ANCHORS USING VIBRATING-WIRE GAUGES

Long-term monitoring of the behavior of ground anchors constitutes an important aspect of the stability of structures reinforced by such structural members. The present paper describes full-scale tests performed on three instrumented grouted anchors in the laboratory and one other instrumented anchor in the field. Due to the long-term reliability, stability, and accuracy, two types of surface-mounted vibrating wire gauges were used to instrument the anchors. A series of vibrating-wire gauges were microwelded on the anchors at certain intervals along their lengths. The performance of these gauges, the load transfer mechanism, the debonding process, creep behavior, and long-term performance of the anchors under loading, unloading, and sustained loading, were investigated in the laboratory. A practical application and test results of an instrumented anchor at Jeffrey Mine in Asbestos, Canada, are described. The results obtained show that this instrumentation technique of grouted anchors is efficient for long-term monitoring.