Experimental study on compound dynamic disaster in deep coal rock under gas and stress loading and unloading

To explore the occurrence mechanism of compound dynamic disasters in coal rocks, this study conducted a true triaxial test simulating gas extraction and stress loading and unloading conditions. To differentiate behaviors among disaster types, the effects of acoustic emission energy, temperature and impact force were analyzed during disaster incubation. The results revealed that different simulation depths lead to varying types of compound dynamic disasters. Compared to rockburst-outburst compound dynamic disasters, outburst-rockburst compound dynamic disasters exhibited higher relative outburst intensity and critical gas pressure. Deep coal rock disasters were characterized by long incubation and short excitation. As a threshold for disaster type transformation, a critical gas pressure range of 2.2-2.8 MPa was identified. During incubation, the temperature generally increased, with greater variation in the coal seam than at the coal-rock interface. During excitation, the temperature dropped sharply, with smaller variation in the coal seam. Outburst-rockburst disasters consistently showed higher temperature variation than rockburst-outburst disasters. Impact force evolution in roadways followed a similar pattern across disaster types: initial impact → intensification → peak → attenuation, with a peak effect. The peak impact force increased linearly with critical gas pressure, with outburst-rockburst peak growth rates being 47.76 times higher than rockburst-outburst peak growth rates. This study provides important insights into the multi-parameter evolution characteristics of deep coal rock compound dynamic disasters, offering a scientific basis for disaster prediction and control. Document Type: Original article Cited as: Zhang, X., Tang, J., Pan, Y., Ren, L., Huang, L., Zhang, Z. Experimental study on compound dynamic disaster in deep coal rock under gas and stress loading and unloading. Advances in Geo-Energy Research, 2025, 16(1): 60-76. https://doi.org/10.46690/ager.2025.04.07