DAI J , LIU B Y． Study on the dynamic mechanical properties of granite with holes under impact loading[J]. Journal of Henan Polytechnic University( Natural Science)，doi: 10.16186/j.cnki.1673-9787.2024070095

doi: 10.16186/j.cnki.1673-9787.2024070095

Received： 2024-07-29

Revised： 2024-08-26

Online： 2025-02-19

Study on the dynamic mechanical properties of granite with holes under impact loading (Online)

DAI Jun, LIU Boyuan

Faculty of Architecture and Civil Engineering,Xi’an University of Science and Technology, Xi’an 710000, Shaanxi, China

Abstract: Objectives To explore the dynamic characteristics and failure processes of granite with through-holes under impact loading. Methods granite specimens with different hole diameters were prepared using a waterjet cutting mechanism. Impact tests were conducted using a split Hopkinson pressure bar device with a rod diameter of 50 mm. Experimental data were recorded using a super dynamic strain gauge, and a high-speed camera was used to capture the failure process of the specimens. The influence of hole size on the dynamic mechanical properties and failure processes of granite under impact loading was analyzed. Results The study results indicate that as the hole size increases, the dynamic compressive strength of the specimens decreases, and the peak strain increases. There is a positive correlation between hole size and both the specific absorbed energy and specific reflected energy, while the transmission capability shows a negative correlation. During the specimen failure process, larger hole diameters exhibit a stronger ability to induce major cracks, with a more pronounced phenomenon of initially promoting and then inhibiting horizontal cracks. More energy is absorbed when stress waves propagate through the specimen, leading to a faster development of internal fractures and the generation of more debris upon failure. Conclusions For small-diameter specimens, increasing the hole size has a smaller effect on strain than on strength. For large-diameter specimens, increasing the hole size has a greater effect on strain than on strength. The failure process of small-diameter specimens is less related to the hole size, while larger hole sizes more clearly induce major cracks and show a more pronounced phenomenon of initially promoting and then inhibiting horizontal cracks. Although small-diameter specimens can withstand greater pressure before failure, they exhibit fewer pre-failure signs and are closer to brittle failure. Large-diameter specimens are closer to ductile failure. The research findings provide valuable references for the stability and failure processes of surrounding rock in tunnels and underground spaces during excavation or disaster events.

Key words: Porous granite; impact load; energy analysis; failure mechanism; dynamic characteristics