Experimental Investigation on the Granite Erosion Characteristics of a Variable Cross-Section Squeezed Pulsed Water Jet

The exploitation of deep resources and energy needs to break hard rock. Aiming at the problem of deep hard rock fragmentation, this paper proposes a variable cross-section squeezing pulsed water jet technology (SPWJ). SPWJ was generated under pump pressures of 5.2, 6.8, 8.5, 10, 11.9, and 13.8 MPa to carry out erosion experiments. Features such as rock spalling area, erosion depth, volume loss, and decomposition per unit inlet pressure are used to characterize the erosion performance of SPWJ. The results show that SPWJ can effectively crush granite under low input pressure. Granite crushing modes caused by SPWJ are mainly divided into three types: I: drilling type, II: erosion type, and III: cracking type. Compared with continuous water jet (CWJ), SPWJ has better overall erosion ability than CWJ when the erosion pressure is higher than 60 MPa, the dimensionless target distance is greater than 200, and the erosion time is less than 90 s. In addition, the erosion ability of SPWJ is better than that of CWJ under the condition of unit input pressure. The research results provide a reference for further optimizing the performance of SPWJ crushed granite in the future.