Experimental and Numerical Investigation of Hard Rock Breakage by Indenter Impact

Abstract

To investigate the effect of indenter shape, impact energy, and impact velocity on the rock breakage performance, a test device for rock fragmentation by indenter impact was developed to obtain the rock breakage volume, depth, and area under different impact conditions. By comparing the rock breakage volume, depth, area, and specific energy consumption, the results show that indenter shape has a greater influence on the rock breakage performance than that of the impact velocity with the same impact energy, and impact energy plays a decisive role in rock breakage performance with an identical indenter shape and impact velocity. For the lowest to highest specific energy consumption, the order of indenter shape is cusp-conical, warhead, hemispherical, spherical-arc, and flat-top under the same impact energy and velocity, but the cusp-conical indenter is damaged after several impacts. The rock breakage volume, depth, and area all increase with the increase in impact energy, but the effect of the impact velocity could be ignored under the same impact energy. In addition, the rock breakage features of the numerical simulation and experiments are similar, which show that the crushing zone close to the indenter impact point is mainly caused by the high compressive stress, and then radial cracks are caused by the accumulative energy release. The findings of this study will contribute to progress in the performance and efficiency for percussive rock drilling.

Design optimization and feasibility analysis of pneumatic DTH Hammer with self-rotation bit

“…Contact stress can quickly reach an extremely high value and generate the local stress concentration. Thus, the rock-crushing efficiency can be increased significantly [19][20]. The piston repeatedly impacts the drill bit at high speed with a specific frequency when the hammer is working.…”

Experimental and analytical study on key factors of rock breaking under a single indenter

“…All of them have little to do with impact velocity but rock properties. The responses of soft and hard rocks to impact indenter are significantly different, resulting in that the crushing pit of soft rock mass under impact is much smaller than that of hard rock mass 17–19 . In addition, common indenter shapes include wedge‐, conical‐, circular‐, and cruciform‐shaped indenters 20 .…”

“…The responses of soft and hard rocks to impact indenter are significantly different, resulting in that the crushing pit of soft rock mass under impact is much smaller than that of hard rock mass. [17][18][19] In addition, common indenter shapes include wedge-, conical-, circular-, and cruciform-shaped indenters. 20 Among them, the wedge indenter is most commonly used, and the apex angles in the range 90-120 have good effect on rock breaking.…”

Research on the Matching of Impact Performance and Collision Coefficient of Hydraulic Rock Drill

“…Among them, the impact ability of the impact system affects the service durability of the body structure, sealing ring, and connecting bolt. In order to effectively guarantee the continuous working ability of the hydraulic rock drill, more and more scholars pay attention to the research on the relationship between the impact performance of the rock drill and the service durability of its components [1][2][3].…”