Micro-Failure Mechanism Analysis and Test Study for Rock Failure Surface under Water Jet Impact

The rock breaking mechanism by water jets impact has not been clearly recognized as yet for complicated process of rock damage. The test of cutting rocks with submerged high-pressure water jets impact by a numerical controlling jet cutting machine are conducted. Then, the test for the pattern of failure surface of cutting slots and dilapidated slices are performed with scanning electron microscope (SEM) to study micro failure mechanism of rocks with water jets impinging. The result shows two types of rectangle shape and shallow funnel shape craters in the rock matrixes. The analysis shows that the micro-mechanism of rock failure due to water jets impingement is a brittle fracture in the condition of tensile and shearing stress.