Abstract

New type of rock excavation method using a waterjet system is being developed to secure economic feasibility and to reduce vibrations during excavation. In waterjet rock excavation, overlapping of cutting width is essential for high efficiency. In this study, cutting experiments for granite specimens were performed using abrasive waterjet system according to the overlapping ratio and standoff distance. Based on the experimental results, the granite cutting performance was analyzed according to the overlapping ratio. In addition, removal shapes of the cross-section were analyzed interms of the cutting depth, width, and volume after waterjet cutting. When the overlapping ratio is less than 58%, rock specimens are partially removed due to the insufficient overlapping ratio. However, when the overlapping ratio exceeds 67%, overcutting phenomenon is observed. For the partial overlapping ratio (i.e., 25~75%), cutting efficiency is increased in the removal volume. This study is expected to be used as the important basic data for determining the optimum overlapping ratio when the waterjet system is applied for rock excavation.