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<p>In deep mining engineering, high in situ stress rock masses subjected to the combined action of excavation unloading and dynamic disturbance can induce instability disasters in roadway surrounding rock. This study conducted three types of tests—conventional true triaxial compression, unilateral unloading, and unilateral unloading–disturbance—on siliceous sandstone using a true triaxial unequal stress unloading–disturbance test system. Combined with acoustic emission (AE) monitoring, the stress–strain response, AE parameter evolution, and fracture modes were comparatively analyzed, revealing the mechanical response laws of high in situ stress rock masses under coupled excavation unloading and dynamic disturbance. The results indicate that: (1) Unilateral unloading significantly weakens the peak strength (13.1% reduction at <i>σ</i><sub>2</sub> = 25&#xa0;MPa), inducing stepped plate-splitting failure on the unloading surface; (2) the disturbance load (3 ~ 15&#xa0;MPa) reduces the cumulative AE ring-down counts to 10% of the undisturbed state, compressing the b-value fluctuation range to 0.82 ~ 1.74; (3) the proportion of tensile cracks increases from 88% (<i>σ</i><sub>2</sub> = 15&#xa0;MPa) to 98% (<i>σ</i><sub>2</sub> = 25&#xa0;MPa) with increasing intermediate principal stress, transforming the failure mode from tension-shear composite to pure splitting; (4) peak strength decreases with increasing disturbance amplitude, accelerating material brittle failure; and (5) stepped spalling on the free surface and radial crack networks on the solid side constitute an asymmetric failure configuration. This experiment provides a mechanical basis for preventing dynamic disasters in deep roadway surrounding rock.</p>

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Mechanical Behavior and Acoustic Emission Response Mechanism of Siliceous Sandstone under True Triaxial Unloading–Disturbance

  • 期刊论文

  • 发表日期：

    2026年1月20日

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  • Rui Luo,
  • Yanlin Zhao,
  • Tianyao Li,
  • Zhe Tan,
  • Ximing Luo,
  • Yingjie Zhang,
  • Minzhen Zhang

摘要

In deep mining engineering, high in situ stress rock masses subjected to the combined action of excavation unloading and dynamic disturbance can induce instability disasters in roadway surrounding rock. This study conducted three types of tests—conventional true triaxial compression, unilateral unloading, and unilateral unloading–disturbance—on siliceous sandstone using a true triaxial unequal stress unloading–disturbance test system. Combined with acoustic emission (AE) monitoring, the stress–strain response, AE parameter evolution, and fracture modes were comparatively analyzed, revealing the mechanical response laws of high in situ stress rock masses under coupled excavation unloading and dynamic disturbance. The results indicate that: (1) Unilateral unloading significantly weakens the peak strength (13.1% reduction at σ2 = 25 MPa), inducing stepped plate-splitting failure on the unloading surface; (2) the disturbance load (3 ~ 15 MPa) reduces the cumulative AE ring-down counts to 10% of the undisturbed state, compressing the b-value fluctuation range to 0.82 ~ 1.74; (3) the proportion of tensile cracks increases from 88% (σ2 = 15 MPa) to 98% (σ2 = 25 MPa) with increasing intermediate principal stress, transforming the failure mode from tension-shear composite to pure splitting; (4) peak strength decreases with increasing disturbance amplitude, accelerating material brittle failure; and (5) stepped spalling on the free surface and radial crack networks on the solid side constitute an asymmetric failure configuration. This experiment provides a mechanical basis for preventing dynamic disasters in deep roadway surrounding rock.