DEM Simulation on the AE Characteristics of Sandstone Containing Hole under Different Filling Conditions Based on Moment Tensors

The filling material significantly affects the structural stability of geotechnical engineering, which makes the occurrence of instability and failure of rock mass structure with holes uncertain. To explore the acoustic emission response mechanism of sandstone containing hole under different filling conditions under loading, the discrete element method and moment tensor theory were used to simulate the uniaxial compression of sandstone with holes under different filling conditions, and the types, amplitude distribution and b-value characteristics of acoustic emission events in the failure process were analyzed in this study. The results show that: (1) under filling conditions b and c, the strength growth rates of circular, rectangular, and trapezoidal specimens are 2.75%, 7.12%, 4.35%, and 8.30%, 13.14%, 18.03%, respectively; (2) the addition of filling material leads to more intense AE events, with the intensity of AE activity positively correlated with the strength of the filling material. The cumulative number of AE events and AE rate of filled specimens are higher than those of unfilled specimens; (3) under filling condition c, the proportion of shear-type AE events is higher than that in other filling conditions, and the AE frequency-amplitude distribution follows a normal distribution; (4) under the same filling condition, the AE b value of circular hole sample is the largest, followed by rectangular and trapezoidal holes. Under the same hole shape, the b value is the smallest under the condition of filling c, and the b value is the largest under the condition of filling a. The findings can provide some reference for the analysis of acoustic failure characteristics of rock mass with holes under different filling conditions in engineering.