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<p>Aiming at the problem of deep surrounding rock instability induced by roadway excavation or mining disturbance, the true triaxial loading system was used to conduct graded cyclic maximum principal stress <i>σ</i><sub>1</sub> and intermediate principal stress <i>σ</i><sub>2</sub> tests on sandstone to simulate the effect of mining stress in actual underground engineering. The influences of each principal stress cycle on the mechanical properties, acoustic emission (AE) characteristics, and fracture characteristics of sandstone were analyzed. The damage characteristics of sandstone under true triaxial cyclic loading were studied. Furthermore, the damage constitutive model of rock mass under true triaxial cyclic loading was established based on AE cumulative ringing count. The quantitative investigation was conducted on cumulative-damage changes in circulating sandstone, which elucidated the mechanism of damage deterioration in sandstone subjected to true triaxial cyclic loading. The results show that the influence of the graded cycle <i>σ</i><sub>1</sub> on limit maximum principal strain <i>ε</i><sub>1max</sub> and limit minimum principal strain <i>ε</i><sub>3max</sub> was significantly greater than that of the limit intermediate principal strain <i>ε</i><sub>2max</sub>. Graded cycle <i>σ</i><sub>2</sub> had a greater impact on <i>ε</i><sub>2max</sub> and a smaller impact on <i>ε</i><sub>3max</sub>. The elasticity modulus of sandstone decreased exponentially with the increased cyclic load amplitude, while the Poisson ratio increased linearly. <i>b</i> of AE showed a trend of increasing, decreasing, slightly fluctuating, and finally decreasing during cycling <i>σ</i><sub>1</sub>. <i>b</i> showed a trend of slight fluctuation, large fluctuation, and finally increase during cycling <i>σ</i><sub>2</sub>. Sandstone specimens experienced mainly tensile failure, tensile-shear composite failure, and mainly shear failure with increased initial <i>σ</i><sub>2</sub> or <i>σ</i><sub>3</sub>. This was determined by analyzing the rise angle-average frequency of the AE parameter, corresponding to the rock specimens from splitting failure to shear failure. Besides, the mechanical damage behavior of sandstone under true triaxial cyclic loading could be well described by the established constitutive model. At the same time, it was found that the sandstone damage variable decreased with increased <i>σ</i><sub>2</sub> during cycling <i>σ</i><sub>1</sub>. The damage variable decreased first and then increased with increased <i>σ</i><sub>3</sub> during cycling <i>σ</i><sub>2</sub>.</p>

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Research on damage characteristics and constitutive model of rock mass under true triaxial cyclic loading based on acoustic emission

  • 期刊论文

  • 发表日期：

    2025年5月1日

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  • Ying-ming Li,
  • Chao-tao Fan,
  • Chun-liang Dong,
  • Guang-ming Zhao,
  • Xiang-rui Meng,
  • Xiang-jun Wang,
  • Wen-qiu Shi,
  • Xin-wen Wu,
  • Jiang-huai Gao

摘要

Aiming at the problem of deep surrounding rock instability induced by roadway excavation or mining disturbance, the true triaxial loading system was used to conduct graded cyclic maximum principal stress σ1 and intermediate principal stress σ2 tests on sandstone to simulate the effect of mining stress in actual underground engineering. The influences of each principal stress cycle on the mechanical properties, acoustic emission (AE) characteristics, and fracture characteristics of sandstone were analyzed. The damage characteristics of sandstone under true triaxial cyclic loading were studied. Furthermore, the damage constitutive model of rock mass under true triaxial cyclic loading was established based on AE cumulative ringing count. The quantitative investigation was conducted on cumulative-damage changes in circulating sandstone, which elucidated the mechanism of damage deterioration in sandstone subjected to true triaxial cyclic loading. The results show that the influence of the graded cycle σ1 on limit maximum principal strain ε1max and limit minimum principal strain ε3max was significantly greater than that of the limit intermediate principal strain ε2max. Graded cycle σ2 had a greater impact on ε2max and a smaller impact on ε3max. The elasticity modulus of sandstone decreased exponentially with the increased cyclic load amplitude, while the Poisson ratio increased linearly. b of AE showed a trend of increasing, decreasing, slightly fluctuating, and finally decreasing during cycling σ1. b showed a trend of slight fluctuation, large fluctuation, and finally increase during cycling σ2. Sandstone specimens experienced mainly tensile failure, tensile-shear composite failure, and mainly shear failure with increased initial σ2 or σ3. This was determined by analyzing the rise angle-average frequency of the AE parameter, corresponding to the rock specimens from splitting failure to shear failure. Besides, the mechanical damage behavior of sandstone under true triaxial cyclic loading could be well described by the established constitutive model. At the same time, it was found that the sandstone damage variable decreased with increased σ2 during cycling σ1. The damage variable decreased first and then increased with increased σ3 during cycling σ2.