Experimental and Simulation Study on the Hard Rock–Breaking Characteristics of Disk Cutter under the Water Jet Precutting Kerf

Abstract

The effect of water jet kerf depth (H) and cut spacing (S) on the rock-breaking performance of a disc cutter under water jet precutting kerf was investigated through a full-scale linear cutting test and numerical analysis with a discrete element method (DEM). Rock-breaking force, rock chip, and rock-breaking efficiency are used to evaluate the rock-breaking performance. The rock-breaking experimental results show that the rock failure patterns are closely related to H and S, and distinct rock failure patterns are shown for the different rock-breaking parameters. In addition, this study reveals the variation law of rock-breaking force and specific energy (SE) consumption with H and S. The difference in crack expansion between rock-breaking under conventional and precutting kerf conditions was compared with numerical simulations. The lateral cracks tend to expand toward the bottom of the precutting kerf and are more prone to produce large-sized rock chips in the precutting kerf condition. In addition, the increased H promotes the expansion of the vertical and lateral cracks, which resulted in different rock failure patterns. Therefore, the numerical, and experimental results show that the rock-breaking of the disc cutter under the precutting kerf conditions is promising, which significantly improves the rock-breaking performance of the disc cutter in hard rock conditions.