Acoustic emission characteristics and fracture mechanisms of rock-like models with different superimposed fracture angles
SU Zhandong
ZHU Xiangkun
LIU Xiaoli
TAO Zhigang
HU Nan
YIN Qian
NIU Yao
Abstract：To investigate the failure characteristics of fractured rock masses with varying fracture orientations under external loading,uniaxial compression tests were conducted on rock-like models with loading directions at 25°,35°,45°,and 60°(superimposed fracture angle,β)relative to the fractures.Digital image correlation and acoustic emission techniques were employed.The results show that the compressive strength of the models decreases progressively with increasing β.Whenβ is small,normal stress dominates and makes Mode Ⅰ tensile fracture more likely to occur.Whenβ increases,Mode Ⅱ stress intensity factor dominates,leading to Mode Ⅱ shear fracture becoming the dominant mode.The damage of the model accumulates continuously in the first two deforma-tion stages,and after reaching the corresponding moment of model strength,the ringing count de-creases.The total energy release,average cumulative energy,and energy release rate of the model increase with the increase of β.The greater the rate of model destruction,the more intense the en-ergy release,confirming that rupture is the root cause of energy generation.The model with β=60° has the fewest peak frequency points and the most dispersed distribution.The model with β=35° have a higher distribution of quantities and a more severe damage evolution process.By introducing b-value error analysis,it was found that the sudden change in the b-value curve of the β=35° andβ=45° models at the end of the elastic deformation stage can serve as a precursor to rock mass frac-ture.These findings provide valuable theoretical support for engineering design and stability assess-ment of fractured rock masses.
Keywords：superimposed fracture anglerock-like modelacoustic emissioncharacteristic param-etersfracture mode
Publication Date：2026-01-30
Online Publishing Date：2026-01-28(First online date of this platform, not the publication date of the document)
Pages：13( 61-73 )