Abstract
In order to examine the dynamic mechanical properties, dynamic crack proposition process, and energy loss of fractured rock under dynamic loading, the specimens with different fracture dig angles were processed with Φ50 mm × 50 mm cylindrical sandstone, the impact loading test was conducted on 50 mm stem diameter split Hopkinson pressure bar (SHPB) experiment platform, and the whole process of crack propagation and dynamic failure was recorded using a high-speed camera. As a result, the dynamic mechanical properties such as stress wave fluctuation characteristics, peak strength and stress-strain relationship, crack initiation angle, stress and other dependencies with prefabricated fracture angle of the prefabricated fracture specimens under high strain rate were obtained, and the incident energy, absorbed energy, and energy absorption rates were compared to investigate the energy loss law in the dynamic loading; on the contrary, the effects of different loading rates on the dynamic mechanical properties of the sandstone specimens were identified, and finally a set of findings were presented.
Highlights
Rocks are naturally produced solid aggregates that are composed of one or more minerals, subject to the geological effects of the earth’s internal external forces [1, 2]. ere are a number of defects with different sizes and shapes in rocks, subject to the combined action of external loading and natural environment, and the defects in rocks may be merged and expanded into joints and in turn. e presence of joints leads to discontinuity, nonuniformity, and anisotropy of rocks and substantially changes the stress wave propagation velocity in rocks, thereby altering many properties of rocks and resulting in instability failure of rocks
The failure process of rocks and various physical and mechanical properties of rocks can be obtained from the rock full stress-strain curves derived from uniaxial compression, triaxial compression, and other static load tests; under dynamic loading, the dynamic mechanical properties during the rock fracture process can be obtained from the impact test. e rock fracture process refers to the process from energy acquisition to energy release
The specimens with different fracture dig angles were processed with Φ 50 mm × 50 mm cylindrical sandstone, the impact loading test was conducted on 50 mm stem diameter split Hopkinson pressure bar (SHPB) experiment platform, and the whole process of crack propagation and dynamic failure was recorded using a high-speed camera
Summary
Rocks are naturally produced solid aggregates that are composed of one or more minerals, subject to the geological effects of the earth’s internal external forces [1, 2]. ere are a number of defects with different sizes and shapes in rocks, subject to the combined action of external loading and natural environment, and the defects in rocks may be merged and expanded into joints and in turn. e presence of joints leads to discontinuity, nonuniformity, and anisotropy of rocks and substantially changes the stress wave propagation velocity in rocks, thereby altering many properties of rocks and resulting in instability failure of rocks. The degree of rock breaking caused by blasting should be precisely controlled, and the rock breaking fragmentation, blasted pile shape, and blasting volume are required to be reasonably controlled in the work of engineering blasting so that the mechanical efficiency can be fully used In this sense, an attempt to investigate the dynamic properties of fractured. Deng et al [13] investigated the damage mechanical properties of rocks and the law of energy dissipation under dynamic loading by the SHPB impact test and found that the degree of rock fracture was positively correlated with strain rate. The specimens with different fracture dig angles were processed with Φ 50 mm × 50 mm cylindrical sandstone, the impact loading test was conducted on 50 mm stem diameter split Hopkinson pressure bar (SHPB) experiment platform, and the whole process of crack propagation and dynamic failure was recorded using a high-speed camera. According to the SHPB test results, the engineering mechanical properties of rocks were inferred and some results were obtained
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