Mechanical properties and reinforcement effect of jointed rock mass with pre-stressed bolt

Pre-stressed bolt anchorage is the key technology for jointed rock masses in rock tunnelling, slope treatment and mining engineering. To investigate the mechanical properties and reinforcement effect of jointed rock masses with pre-stressed bolts, in this study, uniaxial compression tests were conducted on specimens with different anchoring types and flaw inclination angles. ABAQUS software was used to verify and supplement the laboratory tests. The laws of the uniaxial compressive strength (UCS) obtained from the numerical simulations and laboratory tests were consistent. The results showed that under the same flaw angle, both the UCS and elastic modulus of the bolted specimens were improved compared with those of the specimens without bolts and the improvements increased with an increase in the bolt pre-stress. Under the same anchoring type, the UCS and elastic modulus of the jointed specimens increased with an increase in the flaw angle. The pre-stressed bolt could not only restrain the slip of the specimens along the flaw surface but also change the propagation mode of the secondary cracks and limit the initiation of cracks. In addition, the plot contours of the maximum principal strain and the Tresca stress of the numerical models were influenced by the anchoring type, flaw angle, anchoring angle and bolt position.