Effects of dynamic velocity on the dynamic compressive mechanical properties and energy evolution of coal specimens

ABSTRACT

Dynamic compressive parameters of coal specimens were driven not only by impact velocities, but also by preloaded confining pressure, and impact loading methods. This paper investigates the influences of dynamic parameters based on the split Hopkinson pressure bar (SHPB) experimental data obtained from the dynamic compressive impact tests on 12 coal specimens under four different impact velocity. The analysis of the experimental results confirmed that with an increase of dynamic velocity, and then the dynamic compressive strength is constantly increases. When the dynamic velocity is 8.10 m/s, and then reacheed the maximum dynamic strength of 25.11 MPa of the coal specimen. Furthermore, the dynamic velocity of 8.10 m/s was defined as the threshold value of the dynamic strength increased. The greater of dynamic velocity, the higher degree of fragmentation of the coal specimens. The transmitted energy, reflected energy, and absorbed energy of coal specimens shows a directly proportional relationship with the incident energy. The results highlight the first and second dynamic deformation moduli can clearly explained the deformation laws of elastic and plastic stages of the coal specimens. It is also found that the maximum of strain rate is 177.28 s⁻¹ and the maximum ultimate strain is 2.47 × 10⁻²of the coal specimens. The research results were beneficial to supplement the coal-rock dynamics theory, thus also providing a direction for safety and effective mining and crushing in coal mines.

KEYWORDS:

• Rock dynamic mechanics
• coal specimens
• impact velocity
• failure characteristics
• energy dissipation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors contributions

Han Meng – Writing original draft, Investigation. Yuzhong Yang: Writing, review & editing. Wei Hou: Investigation. Xinwang Li – Funding acquisition. Li Chen – Methodology & Conceptualization. Daming Yang – Conceptualization, Methodology. Chenlin Wang – Review & editing. Longlong Pang – Formal analysis, Validation.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [52104081]; National Natural Science Foundation of China of key projects supported by the Henan Province United Fund [U1904210]; Natural Science Foundation of Hebei Province [E2022402031, E2020402075, E2022402014 and E2020402041]; Natural Science Foundation of Henan Province [232300420076]; Hebei Natural Foundation Ecological Smart Mine Joint Fund Project [E2020402036]Hebei Province Higher Education Science and Technology Research Project [BJK2023080]; Handan City Science and Technology Research and Development Plan Project [194221210008-34].

Notes on contributors

Han Meng

Han Meng mainly engaged in original draft and investigation

Yuzhong Yang

Yuzhong Yang mainly engaged in review and editing

Wei Hou

Wei Hou mainly engaged in investigation

Xinwang Li

Xinwang Li mainly in analysis and technology research

Li Chen

Li Chen mainly engaged in methodology and conceptualization

Daming Yang

Daming Yang mainly engaged in conceptualization and methodology

Chenlin Wang

Chen Lin Wang mainly engaged in review

Longlong Pang

Longlong Pang mainly engaged in formal analysis and validation