SUN Xiaoming, SHI Fukun, DING Jiaxu, TAO Zhigang, HE Linsen, YANG Liu, ZHANG Yong, MIAO Chengyu. 2024: Triaxial mechanical properties and precursors of instability damage in rocks with different laminar dip angles. Journal of Mountain Science, 21(2): 648-661. DOI: 10.1007/s11629-023-8085-7
Citation: SUN Xiaoming, SHI Fukun, DING Jiaxu, TAO Zhigang, HE Linsen, YANG Liu, ZHANG Yong, MIAO Chengyu. 2024: Triaxial mechanical properties and precursors of instability damage in rocks with different laminar dip angles. Journal of Mountain Science, 21(2): 648-661. DOI: 10.1007/s11629-023-8085-7

Triaxial mechanical properties and precursors of instability damage in rocks with different laminar dip angles

  • To investigate the mechanical failure characteristics of volcanic breccia with different bedding dip angles in deep layers, triaxial compression experiments were conducted on specimens taken from volcanic rock layers in the Junggar Basin, Xinjiang. By changing the confining pressure, we compared the mechanical properties, acoustic emission characteristics, and fractal features of the acoustic emission sequence for volcanic breccia with different bedding dip angles. The research results indicate that as the bedding dip angle increases, peak strength, internal friction angle, and cohesion exhibit a "U-shaped" variation pattern. The correlation dimension of the acoustic emission amplitude was calculated using the G-P algorithm, revealing that volcanic breccia exhibits fractal characteristics. Furthermore, a positive correlation between the correlation dimension and the bedding dip angle was observed. When the stress of the test specimen reaches 0.8 \sigma _c , there is a significant decrease in the fractal dimension, serving as a criterion for predicting the failure of the specimen. By analyzing the changes in fractal dimension at different stress levels, the slope of the fractal dimension \Delta D < -0.5 can be used as a precursor to failure for test specimens with a bedding dip angle of 15°\le \beta \le 45° . Similarly, when the bedding dip angle of the specimen is 0°\le \beta < 15° or 45° < \beta \le 90° , \Delta D < 0 can be considered as a precursor to specimen failure. This study provides theoretical references for understanding the failure patterns of volcanic rock.
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