To comprehensively understand the mechanical response of a rock-coal combination structure containing a weak layer, a series of laboratory static loading and impact loading experiments were conducted. The results showed that under static load, the sliding process of the rock coal structure was relatively slow, and fragments can be observed. Under the action of horizontal impact loading, the whole coal stratum slipped out rapidly, and the process lasted only 0.05 s. Under the horizontal and axial impact loads, the coal stratum remained stable first, and then it slipped out as a whole under the action of static load. Additionally, a sliding instability criterion of a rock coal structure containing a weak layer was established based on theoretical analysis. The key parameter P value was checked through a numerical simulation experiment. It was found that the value was linearly related to the mechanical properties of the weak layer and overburden stress, and the experimental results coincided with the theoretical results. Finally, the relationship between sliding rockburst and strain rockburst was discussed, and these results can provide an important scientific basis for the prevention and control of dynamic disasters in deep mining.

Discreteness of mechanical property affected by the intimal damage, which emerged with various degrees of material composition and geological structure, is the difference in porosity macroscopically. Although various porosities directly affect fracture activity, damage evolution and mechanical behaviour of coal bring on the bump‐prone assessment error, and disaster happened “ahead of time” in deep underground energy source exploration, little research to date has focused on them. In this paper, the mechanical properties of bump‐prone coal samples with different porosities were studied by uniaxial compression test and the initial damage caused by gangue and organic fracture in coal observed by CT. The result indicated that the evolution of coal strength and the logarithm of porosity were expressed by a linear negative correlation and the elastic modules decreased with the initial damage increased. A new quantitative description of damage variables is established by theoretical derivation to reflect the process of cracks formation and expiation in coal, based on volumetric strain and initial porosity. According to the Mohr–Coulomb principle, the effective stress of coal sample with higher the porosity is more likely to reach the shear strength and destruction. The amplitudes and accumulation of AE energy and charge pulse indeed vary with the stress loading stages and strength. The frequency of AE waveform is dominated in three bands (1∼50 kHz, 100∼150 kHz, and 175∼200 kHz) and that of charge induction had one frequency band 1∼100 Hz, and the amplitudes of time domain and main frequency components increased with stress improved. Both of them originated from cracks and belong to homologous signals, crack development bound to be accompanied by stress wavelet, not necessarily free charge; meanwhile, charge pulse being emerged means there must be cracks interaction and the acoustic emission signals are generated prior to charge induction.

A method for precise localization of seismic sources in rock mechanics was proposed. The method combines accurate picking of P-wave arrival times with an analysis-based filtering of anomalous arrivals and a joint localization approach using genetic algorithms (GA). The method was applied to locate fracture surfaces in rock materials and in mining engineering. To mitigate the impact of sensor timing accuracy, traditional iterative methods, and the selection of initial iterative values on localization, an improved STA/LTA method based on time-frequency analysis was used to pick the P-wave arrival times. A logic probability density function of the analysis-based solutions for different sensor combinations was employed to filter out anomalous arrivals. Genetic algorithms were then used to locate the clear arrivals from filtered data. The method was validated through tests on pencil lead break and coal-interlayer-rock compression, as well as controlled blasting experiments. The results show that combining precise filtering using variational mode decomposition (VMD) after pre-bandpass filtering with the improved STA/LTA method significantly enhances the accuracy of P-wave arrival time picking. The combination of the analysis method for filtering the impact of anomalous arrivals on positioning accuracy and the genetic algorithm, which is globally applicable and not influenced by initial values, allows for more accurate localization of seismic sources in rock material testing and mining engineering. This method has greater practical engineering application value compared to traditional iterative methods and linear positioning methods.

Rock burst is a catastrophic dynamic disaster caused by sudden failure and instability of coal, which brings threats to deep coal mining; the AE‐charge signals and the fragment distribution are related to both mechanical properties of coal and disaster early warning directly. Hence, the variation of AE and charge induction during coal failure, fractal feature of coal fragments, and their relationship should be studied in depth. In this paper, uniaxial loading test was carried out for coal with bursting tendency samples produced by blocks cored from 800 m depth in Xiaoqing coal mine of the Tiefa Coal Group in northeast China; the fractal characteristics of specimens are obtained by using the statistical fractal method. The mechanics of similarities and differences between acoustic emission and charge signal is investigated by using loading experiments and theoretical analysis. It is found that the fragments of coal have good self‐similarity properties; the fractal dimension of the specimens is in the range 2.085–2.521, the maximum range being 2.300–2.468, which is slightly higher than that of rock. The high‐amplitude pulses of the acoustic emission and charge are concentrated in the macroscopic fissure development and expansion stage but they have asynchronous characteristics between them. The charge generation process is accompanied by the inhomogeneous deformation and sliding friction; the friction slip is the major one and is analysed theoretically. A theoretical model for the force‐electric coupling relationship is established. The statistical results show that both the acoustic emission and the charge signal accumulation have a significantly proportional relationship with the fractal dimension. Both the acoustic emission and charge signal reveal coal breakage evolution process, which will help in obtaining the precursor information on coal failure. Furthermore, the monitoring results can predict the extent of coal mass instability.