The Influencing Factors of the Rock Breaking Effect under Particle Water Jet Impacting

To highlight the patterns of rock fractures in the dynamic indentation particle water jet more accurately, and to identify optimal process parameters for dynamic indentation operations, orthogonal tests were performed for rock fractures in dynamic indentation involving particle water jet to determine the impact of various factors in particle water jet on rock-breaking performances. Then, considering the impacts of each individual factor, volumetric fractions, diameters, jet angles and other key factors were reviewed to evaluate their impacts on rock-breaking performances. Test results showed the influencing factors of particle water jet on rock-breaking performances could be placed in following order in accordance with the intensity of their impact, including: jet time, volumetric fraction of particles, diameters, jet angles and distances. The optimal particle volumetric fraction was determined to be 2.0%; the optimal particle diameter was determined to be 1.5 mm, and the optimal jet angle was determined to be 15°. Relevant research results showed that the depths of formed holes had a quadratic function relationship with both volumetric factors and particle diameters and a quartic function relationship with jet angles. On the other hand, volumes of holes had a tertiary function relationship with particle volumetric factors, particle diameters and jet angles. The conclusions after evaluating the results of the study might provide reliable a theoretical foundation for the application and promotion of particle impact drilling techniques.