Study on Optimization of Key Parameters for High-Pressure Water Jet Reaming Equipment of Anchor Holes in Soft Rock Roadways

To solve the problems of easy fracture of reaming cutter arms and mechanical jamming leading to equipment damage when mechanical reaming equipment is used for anchor hole reaming in soft rock roadways, this study proposes the development of a high-efficiency reaming device with a simple structure. This study combines theoretical analysis, numerical simulation, and laboratory experiments to systematically investigate the key parameters of high-pressure water jet reaming equipment. The results show that under the same conditions, the maximum velocity of the high-pressure water jet decreases with an increase in the number of nozzles and the nozzle spacing. Although the correlation between the maximum jet velocity and nozzle angle is weak, the jet velocity acting on the anchor hole wall reaches its peak at a nozzle angle of 60°. Based on the simulation results, a 1:1 scale nozzle model was manufactured using 3D printing technology, and high-pressure water jet reaming experiments and bolt pull-out tests were carried out at a pressure of 20 MPa. The experimental results demonstrate that the optimal reaming effect is achieved with a nozzle configuration of 3 nozzles, 10 mm spacing, and a nozzle angle range of 45–60°. Specifically, after reaming with the nozzle at a 60° angle and 10 mm spacing, the bolt anchoring force reaches 51.99 kN, representing a 41.16% increase in anchoring strength compared with conventional anchoring. This research provides technical support for the engineering application of anchor hole reaming technology in soft rock roadways and is of great significance for improving the support effect of soft rock roadways.