State Key Laboratory of Water Resources Protection and Utilization in Coal Mining, National Institute of Clean-and-Low-Carbon Energy
China Energy Investment Group Co.
College of Energy and Mining Engineering, Shandong University of Science and Technology
Qingdao Geological Exploration of China Metallurgical Geology Bureau

岩石内部损伤演化是导致岩土工程灾害的原因之一，揭示岩石破裂过程中的关键参数响应特征可为岩石破坏后失稳状态识别提供依据，对于岩体工程灾害预警防控至关重要。通过循环加载−卸载(加卸载)试验制备不同损伤程度粉砂岩试样，利用损伤试样开展单轴加载试验，分析试样损伤程度与波速关系及声发射演化规律，探讨不同损伤程度岩石的声发射响应机制。结果表明：(1) 损伤试样纵波波速随着损伤程度增加呈线性减小趋势，但声发射振铃计数由阶段性递增转变为加载全过程迅速增加，声发射能量在屈服阶段由小幅度突增转变为快速增加。(2) 反映岩石内部不同尺度裂隙发展趋势的声发射b值峰值区由峰后破坏阶段向压密阶段转移，造成峰后破坏阶段失稳特征不明显，反映岩体内部声发射源集中程度和能量尺度的S值在压密至屈服阶段由低位中幅度波动转变为高位小幅度波动，表明岩石在峰前阶段产生非稳定破坏。(3) 损伤试样破裂过程随着损伤程度增加由晶间滑移主导型转变为裂隙发育主导型，导致声发射高频低能(400~800 kHz、0~250 aJ)信号由零星出现转变为加载全过程密集分布，以及高频信号带变宽。(4) 损伤岩石内部裂隙发育程度不同是导致声发射响应机制差异化的根本原因，岩石内部裂隙密度随着损伤程度增加而增大，造成其在受载过程中由渐进式稳定破坏模式向突发式非稳定破坏模式转变，同时加载过程中声发射信号活跃度及强度增强。研究获得了不同损伤程度岩石的声发射参数特征，可为工程岩体损伤程度识别提供理论依据。

The evolution of rock internal damage is one of the causes of geotechnical engineering disasters, and revealing the response characteristics of key parameters during the rock failure could provide a basis for the identification instability state after rock failure, which is of great importance for the early warning and prevention of rock engineering disasters. Herein, the siltstone specimens with different damage degrees were prepared by cyclic loading-unloading tests, and uniaxial loading tests were carried out with the damaged specimens. On this basis, the relationship between the damage degree of specimen and the wave velocity, as well as the acoustic emission (AE) evolution law, was analyzed, and the AE response mechanism of rocks in different damage degree was discussed. The results show that: (1) The P-wave velocity of damaged specimens decreases linearly with the increase of damage degree, but the AE ringing counts change from periodical increasing to rapid increasing during the whole loading process. The AE energy increases rapidly from a small amplitude at the yield stage. (2) The peak value of AE b value reflecting the trend of development of internal fractures at different scales, transfers from the post-peak failure stage to the compaction stage, resulting in the unobvious instability characteristics of post-peak failure stage. The S value, reflecting the concertration and energy scale of AE sources within the rock mass, varies from medium amplitude fluctuation at low value to small amplitude fluctuation at high value in the compaction to yield stage, indicating that unstable failure occurs in the pre-peak stage. (3) The breaking process of damaged specimen changes from the dominant type of intergranular slip to the crack development with the increasing of damage degree. Thus, the AE high-frequency and low-energy signals (400-800 kHz, 0-250 aJ) vary from sporadic appearance to intensive distribution during the whole loading process, and the high-frequency signal band becomes wider. (4) The different development degrees of cracks in the damaged rock is the basic reason for the differentiation of AE response mechanism. The density of microcracks in rock increases as the damage degree increases, which lead to the transition of progressive stable failure mode to burst unstable failure mode during the loading process, and the enhancement of AE signal activity and intensity. Generally, the characteristics of AE parameters of rocks with different damage degrees were obtained in this study, which could provide theoretical basis for the damage identification of engineering rock mass.

煤炭开采水资源保护与利用全国重点实验室开放基金项目(GJNY-21-41-17)；国家自然科学基金面上项目(52274086)；国家自然科学基金青年基金项目(52004012)

张凯，张东晓，赵勇强，等. 损伤岩石声发射演化特征及响应机制试验研究[J]. 煤田地质与勘探，2024，52(3)：96−106.

ZHANG Kai，ZHANG Dongxiao，ZHAO Yongqiang，et al. Experimental study on acoustic emission evolution characteristics and response mechanism of damaged rocks[J]. Coal Geology & Exploration，2024，52(3)：96−106.