Experimental and numerical studies on progressive debonding of grouted rock bolts

Understanding the mechanism of progressive debonding bolts is great significance for underground safety. In this paper, both laboratory experiment and numerical simulation pull-out tests were performed. The experimental test specimens prepared using cement mortar material, a relationship between strength bolt uniaxial compressive (UCS) material specimen was established. locations crack developed in process identified acoustic emission (AE) technique. reproduced 2D Particle Flow Code (PFC ) with calibrated parameters. results show that axial displacement at peak load during approximately 5 mm cement-based grout all strength. contrast, increased UCS confining medium. Under load, cracks propagated to less than one half anchorage length, indicating lag propagation transmission. dilatation rock induced extended force field along direction; and, it as major contributing factor failure bolt.