DAI J, LIU B Y. Dynamic mechanical properties of granite containing holes under impact loading[J]. Journal of Henan Polytechnic University(Natural Science) , 2025, 44(3): 172-180.

doi: 10.16186/j.cnki.1673-9787.2024070095

Received:2024/07/29

Revised:2024/09/30

Online:2025-04-18

Dynamic mechanical properties of granite containing holes under impact loading

DAI Jun, LIU Boyuan

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

Abstract: Objectives The study aims to investigate the dynamic mechanical behavior and failure mechanisms of granite containing cavities under impact loading， a critical issue during tunnel excavation and deep mine roadway development， where rock masses with voids are prone to dynamic disturbance-induced failure.  Methods Granite specimens with different hole diameters were fabricated using waterjet cutting. Impact tests were conducted using a 50 mm diameter split Hopkinson pressure bar （SHPB） system. A dynamic strain gauge recorded the stress-strain data， and a high-speed camera captured the failure process. The effects of hole size on dynamic mechanical properties and failure modes were analyzed. Results As hole diameter increases， the dynamic compressive strength decreases， while the peak strain increases. Hole diameter shows a positive correlation with both specific absorbed energy and specific reflected energy， and a negative correlation with transmitted energy. Larger holes induce more prominent major cracks and exhibit a clearer trend of promoting and then inhibiting horizontal crack propagation. More stress wave energy is absorbed， accelerating internal fracture development and producing more debris upon failure. In small-hole specimens， strength is more sensitive to hole size than strain， while in large-hole specimens， strain is more sensitive. Small-hole specimens endure higher stress before failure but exhibit fewer precursors， resembling brittle failure， whereas large-hole specimens demonstrate behavior closer to ductile failure.  Conclusions This study reveals how hole size affects the dynamic compressive strength， energy dissipation behavior， and failure evolution of granite under impact loading. These findings provide theoretical support for evaluating surrounding rock stability and designing anti-blast support systems in deep underground engineering.

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