Mechanical damage characteristics and acoustic emission characteristics of a bolt-slurry interface under cyclic pull-out loading

Abstract

To consider the effects of various mining stresses in an actual project, a comprehensive laboratory pull-out study of the bolting system under different cyclic loads was carried out, a high stiffness MTS815.04 rock mechanics test system and an independently designed indirect pullout test device and an acoustic emission system was used for synchronous monitoring. Damage failure mechanism of bolt-slurry interface under cyclic loading revealed from macroscopic strength and deformation characteristics and microscopic damage in depth. The results are as follows.: (1) Compared with static pull-out loading, the bolting system under cyclic loading will enter the damage failure state earlier. (2) The greater the cyclic loading and unloading rate are, the greater the impact on the bolt-slurry interface, and the easier it is for sudden macroscopic damage to occur. (3) The greater the cyclic load stress amplitude is, the stronger the acoustic emission activity of the bolt-slurry interface, the greater the damage to the bolt-slurry interface, and the easier it is to fail and de-bond. (4) Finally, the acoustic emission energy, energy rate and count can be used to evaluate the damage characteristics of the anchor interface during cyclic drawing, and the analysis results are in good agreement with the macroscopic damage results. The research results can provide a reference for the support design and performance monitoring of full-length anchor bolts under different cyclic loads.