Fracture experiments on anchoring ordered multi-crack body in rock-like materials under uniaxial compression

In order to study the anchoring mechanism of bolts on the ordered multi-crack body, the full-thread glass fiber reinforced plastic (GFRP) is taken as anchor bolts to fully grout the multi-crack body made from cement mortar to prefabricate test pieces under different anchor conditions. The fracture uniaxial compression tests on these pieces are performed using the RMT-150 servo testing machine. According to the results, the concept of the master crack is proposed, and it is recognized that the strength weakening of the ordered multi-crack body is caused by the perforation of master crack. The work mechanisms of the anchor bolts on the crack generation, expansion and perforation of multi-ordered crack rock-like body are studied from the microscopic aspect, and their effects on the peak strength, residual strength and deformation resistance are investigated from the macroscopic aspect. The result shows that the perforation pattern of the ordered multi-crack rock-like body is changed by the anchor bolts from the longitudinal-incline-horizontal pattern to the horizontal-longitudinal-incline one. The master cracks have longer perforation path and are limited by the anchor bolts. It is specifically indicated that the stress intensity factor of the pieces is changed, and the resistance to deformation, peak strength and residual strength are enhanced after anchored by bolts. However, it is not the situation that the more anchor bolts, the more strength of the ordered multi-crack rock-like body, that is, an appropriate density of anchor bolts will get a better support effect.