Effect of metallic abrasive characteristics on waterjet rock cutting performance

Abstract

A new rock excavation method using an abrasive waterjet system is now under development for efficiently creating tunnels and underground spaces in urban areas. This thesis provides a comprehensive overview of research into the use of metallic abrasives to improve the performance of waterjet hard rock cutting. The study explores the properties of various 6 types of metallic abrasives, such as steel shot, steel grit, steel cut wire shot (sphrerical type, cylinder type) and SUS cut wire shot (spherical type, cylinder type), which allows them to penetrate hard rock formations more effectively than conventional garnet abrasives. The methodology used in this study involved conducting laboratory experiments to compare the performance of waterjets with metallic abrasives. The maximum kinetic energy model proposed by Oh and Cho, 2016, was applied to compare the cutting performance of metallic abrasives, and multiple regression analysis was performed between cutting performance and various waterjet operating parameters, energy parameters, and particle characteristics. Various metallic abrasives were utilized to determine the effect of cutting performance according to the operating parameters of water pressure, abrasive feed rate, and standoff distance, and the effect of cutting performance according to particle size and particle size distribution of fresh metallic abrasives and the effect of cutting performance according to particle characteristics were compared and analyzed. Also, various metallic abrasives that have been recycled once were used to check the effect of cutting performance on the number of recycling times, and the effect of cutting performance on particle characteristics was compared with recycled once metallic abrasives. This research concludes that metallic abrasives enhance cutting performance and efficiency in hard rock formations, offering significant potential for tunneling, mining, and construction projects.