The research on the time-frequency characteristics and evolution law of acoustic emission (AE) signals during deformed coal failure is more conducive to understand the damage mechanism of coal. In this study, the experiments of AE monitoring during the intact and deformed coal failure were first conducted under loading axial stress and unloading confining stress conditions. Based on the evolution characteristics of volume strain and AE event rate, the damage process of coal was divided into three stages: nonfracture development stage, stable development stage of fracture, and unstable development stage of fracture. The distribution and evolution of AE waveform time-frequency properties under different damage processes were then analyzed and discussed. Besides, the evolution of the average value of different time-frequency parameters per 200 s for the intact coal and per 25 s for the deformed coal was discussed. The results show that the amplitude of most AE events stabilizes in 40-50 dB during the intact and deformed coal failure. The average amplitude of the deformed coal has an approximate positive correlation with the loading stress. The percentage of AE events with longer duration and rise time increases suddenly before the peak stress for the intact coal and after the peak stress for the deformed coal, which corresponds to the abrupt increase property of the average duration and rise time. For the frequency properties, the peak frequency and frequency centroid of the intact coal are distributed within 50-125 and 75-150 kHz, with those of the deformed coal located within 20-120 and 80-130 kHz, respectively. The average peak frequency and frequency centroid of the intact coal show an upward trend except for the initial fracture closure stage, while the average peak frequency and average frequency centroid of the deformed coal present a downward trend before the peak stress and have a smaller growth after the peak stress. According to the above-mentioned analysis, the sudden increase of the average duration and rise time, the lower average peak frequency, and the lower frequency centroid can be regarded as the precursor for the instability and failure of deformed coal. This research can provide a new idea and theoretical guidance for the early warning of outbursts.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10157862 | PMC |
| http://dx.doi.org/10.1021/acsomega.3c01815 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Joint response of surface subsidence and strong mine earthquake under high-positioned and thick-hard strata in deep coal mine.
Sci Rep
January 2025
College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao, 266590, China.
Multiple active mining faces and extensive excavations under thick-hard strata in deep coal mines result in frequent strong mine earthquakes, often accompanied by significant surface subsidence deformation. Understanding the specific law of surface movement and the spatiotemporal distribution response to intense mine earthquakes is crucial for effectively preventing and mitigating dynamic disasters in deep mines. Utilizing the key layer theory, the intricate strata of the Yingpanhao Coal Mine are systematically delineated, drawing upon the engineering context of working faces 2201 and 2202 within the Ordos Chemical Co.
View Article and Find Full Text PDFDamage analysis and grading control technology of surrounding rock in high geo-stress roadway.
Sci Rep
January 2025
Coal Mine Safety Mining Equipment Innovation Center of Anhui Province, Anhui University of Science and Technology, Huainan, 232001, China.
To investigate the failure mechanism and establish stability control methods for surrounding rock in high geo-stress roadways, this study incorporated the brittle failure characteristics of the surrounding rock mass into a unified strength criterion, developing an elastic-plastic theoretical model to represent rock damage and fracture. Using this model, analytical expressions for the damage rupture radius and stress field distribution are derived, leading to the proposal of a grading control method. The analysis of calculation examples reveals that an increase in stress, damage degree, and the brittleness coefficient of the rock mass results in the expansion of both the plastic damage and damage residual zones.
View Article and Find Full Text PDFSurrounding rock control for the roadway driven under the goafs of small collieries and heading for adjacent advancing face.
Sci Rep
January 2025
School of Mines, Jiangsu Engineering Laboratory of Mine Earthquake Monitoring and Prevention, China University of Mining and Technology, Xuzhou, 221116, China.
Aiming at the problems of complex stress and large deformations in the surrounding rocks of the roadway driven under the goafs of small collieries and heading for adjacent advancing coal face, by numerical modeling and field practice, the failure characteristics of the overlying coal and rocks were investigated, and the stopping and resuming times of the roadway excavation were identified. A zoning-based reinforcement technique was put forward and applied in engineering practice. The results showed that (1) The roadway roof was divided into four zones: "Rolid coal zone", "Residual pillar zone", "Roof caved zone", and "Roof un-caved zone".
View Article and Find Full Text PDFStudy on mechanical properties of sandstone damaged by blasting load under triaxial cyclic loading and unloading.
Sci Rep
January 2025
School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan, 232001, Anhui, China.
To investigate the changes in the strength and deformation of the blast load-damaged sandstone roof plate under cyclic loading and unloading conditions at different confining pressures, a triaxial loading device was used to carry out graded cyclic unloading tests on specimens with different degrees of damage, and the test results were summarized. The effects of blast-load-induced damage, confining pressure and loading stage on the strength, cohesion, internal friction angle, residual strain and volumetric strain were analyzed. (1) Compared with that of the undamaged specimen at a confining pressure of 0 MPa, the peak stress reductions in the vibration-damaged and blast-damaged specimens were 4.
View Article and Find Full Text PDFStudy on dynamic compression characteristics of coal containing gas under different strain rates.
Sci Rep
January 2025
State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan, 232001, Anhui, China.
Article Synopsis
- A new dynamic and static combined loading test system was developed to study how gas-containing coal behaves under different geological conditions, focusing on triaxial dynamic compression tests.
- The effects of strain rate and gas pressure were significant, with lower gas pressures extending the plastic deformation stage at high strain rates, while higher pressures increased brittleness.
- The research revealed that the damage in gas-containing coal primarily occurs through tensile-shear mechanisms, and higher strain rates and gas pressures influence peak stress and strain, aiding in understanding and managing related hazards.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!