Key Takeaways & Executive Findings
- •• Uniaxial compressive strength and elastic modulus increase with loading rate, with a maximum strength increase of 25.15%. • Failure modes are classified into 'slip-crack synchronization' and 'crack-first-then-slip' types, with slip more severe at high loading rates. • Shear cracks dominate at low loading rates (60.01%), while tensile cracks dominate at high loading rates (70.52%). • Total and dissipated energy peaks increase with loading rate, with C & S type exhibiting higher peak energy than S & C type.
Abstract
The geological tectonic zone is closely related to outburst. Taking the outburst coal bodies in tectonic zones as the research object, combined with DIC and AE monitoring technologies and discrete element simulation, the mechanical response, crack evolution and energy characteristics of coal bodies under different loading rates (impact disturbances) were studied. The results show that both the uniaxial compressive strength and elastic modulus are positively correlated with the loading rate, with a maximum increase in compressive strength of 25.15%. The uniaxial compressive strength is more sensitive to impact disturbances. The failure modes of coal bodies can be divided into the ''slip-crack synchronization (S & C) type'' and the ''crack-first-then-slip (C & S) type''. The slip in tectonic zones is more severe at high loading rates. At low loading rates, shear cracks dominate (60.01%), while the proportion of tensile cracks increases significantly (70.52%) at high loading rates. Additionally, the rate of axial crack growth decreases as the loading rate increases. The peak values of total energy and dissipated energy increase significantly with the loading rate, and the peak energy of the C & S type is greater than that of the S & C type. Energy is preferentially released through the slip of tectonic zones and the propagation of radial cracks.
1. Introduction
Coal is the primary energy source in China, which plays the role of ''ballast stone'' in the energy system and plays the role of energy security [1,2]. As a complex phenomenon of dynamic instability, outbursts pose a significant threat to the safe operation of coal mines and the stable supply of coal [3–5]. Since the outburst accident at the Isaac coal mine in the Loire coalfield of France in 1834, scholars have conducted a series of studies on the mechanisms, causes, phenomena, and prevention measures related to outbursts, achieving remarkable results. Through numerous cases of outbursts, it has been observed that these accidents predominantly occur in geological tectonic zones [6,7].
On March 25, 2021, a significant outburst accident occurred at the 15210 intake airflow roadway excavation face of Shanxi Shigang Coal Industry Co., Ltd., resulting in four fatalities. The direct cause of the accident was attributed to several factors: small faults in the 15210 intake airflow roadway excavation face, the development of tectonic coal, the superposition of multiple stresses, a short pre-pumping time for the project, substandard gas extraction, and the comprehensive excavator, which collectively induced the occurrence of an outburst. On April 28, 2006, an outburst accident occurred in the coal excavation roadway of the reverse upward slope in the second cross-cut at the −70 m level of the Pingshilong Coal Mine, located in Tianxin Township, Jiahe County, Chenzhou City. The incident resulted in the deaths of three individuals. The reasons for the accident are as follows: The geological structure of the mine is primarily characterized by folds, accompanied by faults. The main coal-mining seam, Seam VI, poses a significant risk of outburst. The exposed Seam VI unexpectedly thickened to 7 m with a dip angle of 110°, resulting in the formation of a coal bulge. Additionally, the roof and floor of the seam consist of carbon mudstone and sandy mudstone interbedded with silty sandstone, which exhibit excellent closure properties. Furthermore, the coal seam possesses a high gas-bearing capacity. The outburst was triggered by the superimposition of illegal blasting activities.
Loading authentic research manuscript (Pages 1–5)...
Lingran Ren, Liping Li, Jupeng Tang, Yishan Pan, Song Yang, Xin Zhang (2025). Damage and fracture law of outburst coal bodies in tectonic zones under impact disturbances. SinoTechIntel Verified Research. https://doi.org/10.1016/j.ijmst.2025.08.002
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the main objective of this study?
The study investigates the mechanical response, crack evolution, and energy characteristics of outburst coal bodies in tectonic zones under different loading rates (impact disturbances) using DIC, AE monitoring, and discrete element simulation.
How does loading rate affect the mechanical properties of coal?
Both uniaxial compressive strength and elastic modulus increase with loading rate, with a maximum increase in compressive strength of 25.15%. The uniaxial compressive strength is more sensitive to impact disturbances.
What are the failure modes of coal under impact disturbances?
The failure modes are classified into 'slip-crack synchronization (S & C) type' and 'crack-first-then-slip (C & S) type'. Slip in tectonic zones is more severe at high loading rates.
How does loading rate influence crack types?
At low loading rates, shear cracks dominate (60.01%), while at high loading rates, tensile cracks increase significantly to 70.52%. The rate of axial crack growth decreases as loading rate increases.
What is the energy release pattern in coal under impact?
Peak total and dissipated energy increase significantly with loading rate, with C & S type showing greater peak energy than S & C type. Energy is preferentially released through slip of tectonic zones and propagation of radial cracks.
Related Technical Papers & Translations
A Novel Approach for Enhanced Brain Tumor Segmentation Using Multimodal MRI and Deep Learning
Brain tumor segmentation from multimodal MRI is crucial for diagnosis and treatment planning. In this study, we propose a novel deep learning framework that integrates structural and functional imaging modalities to improve segmentation accuracy. Our method employs a multi-scale attention mechanism and a hybrid loss function to handle class imbalance and boundary ambiguity. Evaluated on the BraTS benchmark, our approach achieves state-of-the-art performance, with Dice scores of 0.91, 0.87, and 0.84 for whole tumor, core, and enhancing tumor, respectively. Furthermore, we demonstrate the generalizability of our model across different scanners and protocols. Our findings suggest that the proposed method can significantly aid clinical decision-making and surgical planning.
Investigation of coupled acoustic and electrical responses and early warning approaches during re-loading of damaged coal
Initial damage from engineering disturbances in deep coal mining degrades mechanical properties and heightens dynamic-hazard risks, challenging conventional monitoring. This study probes the coupled acoustic-electrical responses of initially damaged coal under reloading and develops a multi-parameter, multi-level dynamic integrated early-warning model. Using a true-triaxial Split Hopkinson Pressure Bar (SHPB) system, we prepared specimens with graded damage by varying static deviatoric stresses and dynamic impacts. Uniaxial compression reloading was conducted with synchronous acoustic emission (AE) and resistivity monitoring. Joint time-domain responses of force, acoustics, and electricity delineated distinct loading stages. Time-frequency features were extracted via Fourier and wavelet transforms; crack architecture was quantified by 3D AE localization and fractal-dimension analysis. Initial damage markedly reduced load-bearing capacity. Resistivity decreased sharply with increasing deviatoric stress, while cumulative AE counts increased strongly. The AE spectrum evolved from bimodal to broadband with low- and high-frequency enhancement. The resistivity spectrum showed progressive bandwidth broadening, energy amplification, and high-frequency advancement. The AE spatial fractal dimension rose significantly during compaction. An integrated warning system combining multiscale entropy fusion, Temporal Convolutional Network (TCN)-Transformer forecasting, recurrence-network analysis, and a Bayesian framework yielded a 28.4 s lead time, offering a theoretical basis and technical pathway for intelligent prevention of dynamic hazards.
Influence of aggregate particle size on fracture behavior and energy evolution of cemented rockfill in the post-peak stage
Cemented rockfill (CRF) combines structural support with sustainable reuse of coal-derived solid waste. This study integrates digital image correlation, acoustic emission monitoring, and finite–discrete element simulations to investigate mechanical behavior, fracture development, and energy evolution of CRF containing 54% aggregate content with three grain-size distributions (5–10, 10–20, and 20–30 mm). Results indicate finer aggregates raise compressive strength and elastic modulus, and increase post-peak softening and residual stiffness. Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens, with cracks initiating at boundaries and propagating inward. The proportion of failed joints at comparable strains decreases markedly with finer gradation, reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations. Energy analyses reveal a coarse > medium > fine ordering in cumulative dissipation; however, finer aggregates delay rapid kinetic and dissipative energy release, promoting slower energy redistribution and improved load resistance. These findings quantify how aggregate gradation controls deformational mechanisms, crack topology, and energy partitioning, and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility, energy absorption, and structural reliability of CRF in underground engineering.