Bedding Effects on Acoustic Emission and Infrared Radiation of Coal Under Uniaxial Compression
摘要
The mechanical properties and fracture behavior of coal are significantly influenced by bedding structures. This study examined the impact of bedding planes on the failure characteristics of coal samples using a combined acoustic emission (AE) and infrared radiation (IR) monitoring system. Then the overall damage and surface damage variables were determined based on the cumulative AE ringing count and the average infrared radiation temperature (AIRT). Finally, the criterion for predicting failure of coal was proposed based on AE and IR. The results indicated that bedding significantly affected the spatial and temporal evolution characteristics of AE and IR of coal sample under loading. The peak stress and strain exhibit a V-shaped trend with increasing bedding orientations, reaching the minimum value at 60°. Coal failure undergoes three stages: initial damage, damage development, and damage acceleration, and the damage mainly occurs in the late stage of loading. Surface temperature changes in coal samples are related to stress state and failure mode. The b value of AE (bAE) and the fractal dimension value of IR (DIR) were identified as precursors of coal sample failure, with an average stress level of 0.90σc and 0.96σc for AE and IR precursors, respectively. The combined analysis of bAE and DIR provides effective quantitative predictive information. The research results can provide a theoretical and experimental basis for monitoring instability of mining engineering influenced by bedding structures utilizing AE and IR.