砂岩I型断裂过程区全过程发育曲线的声发射簇类研究

doi:10.3724/1000-6915.jrme.2024.0481

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摘要断裂过程区支配着岩石和准脆性材料I型裂缝的发育和扩展，其全过程发育曲线包含主要特征：断裂过程区达到充分发育的长度和相对应的载荷阶段。但由于观测手段和处理方法的局限，目前很少能从试验中获得这个高分辨率的全过程发育曲线。借助声发射技术对砂岩开展三点弯试验，通过改进声发射簇的分析方法和断裂过程区的计算方法，得到砂岩I型裂缝断裂过程区高分辨率的全过程发育曲线。主要研究结论如下：(1) 断裂过程区的全过程发育曲线与材料裂缝的发育模型相吻合，它不仅准确地提供断裂过程区发育完全的长度和载荷阶段，且表明了断裂过程区与材料相关；(2) 根据全过程发育曲线，以断裂过程区充分发育阶段为转折点，曲线可以明显分为2个阶段，即发育阶段和扩展阶段。在发育阶段，断裂过程区的长度随着外载荷的增加而增加，当外载荷达到峰值时，断裂过程区的长度继续增加直至充分发育；在扩展阶段，断裂过程区不再增加，但其长度测量值出现较明显的波动，这可能与断裂过程区扩展阶段的不稳定相关，但波动以充分发育长度为中心，因此可以认为其长度在扩展过程仍保持为常量。试验结果表明，I型裂缝的断裂过程区达到发育完全时所对应的载荷阶段为峰后90%，其长度接近峰值(9 mm)的2倍(17 mm)。通过局部声发射的试验测量验证了I型裂缝断裂过程区的完全发育阶段同黏聚力模型直接相关的结论。

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	张艳1
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	林青2
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	高跃2
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	潘鹏志4

关键词 ：岩石力学, 断裂过程区, 声发射, I型裂缝, 全过程发育曲线, 黏聚力模型

Abstract：A fracture process zone(FPZ) dominates the fracture initiation and propagation in rock and quasi-brittle materials. The complete development curve involves two FPZ characteristics：the fully-developed FPZ length and its corresponding loading stage. However，due to limitations in observation techniques and processing approaches，it is rare to have the full curve of the FPZ development in the literatures. In this study，a series of mode I sandstone beams under three-point bending are employed to induce the mode I fractures for laboratory testing，where acoustic emission(AE) is used to observe the fracture process. By employing an improved approach to analyze the AE cluster and determine the FPZ boundary，a full curve of the FPZ development in the mode I fracture is obtained. The main conclusions are as follows：(1) the derived curve of the FPZ development aligns well with the theoretical model，which not only provides accurate information of the FPZ(i.e.，the fully developed FPZ length and its corresponding loading stage) but also indicates that the FPZ is related to the material properties. (2) Based on the full curve，the FPZ can be divided into two parts：FPZ initiation and FPZ propagation，with the transition position occurring when the FPZ reaches its fully-developed stage. During the FPZ initiation，the FPZ length increases when the external load increases. Once the peak load is reached，the FPZ continues to grow until the fully-developed FPZ occurs. For the FPZ propagation，the length FPZ remains relatively constant，though fluctuations are observed in the curve，probably due to instability in FPZ propagation. However，these fluctuations are centered around the length of the fully developed FPZ，allowing it to be treated as a constant. Experimental results demonstrate that the FPZ in mode I fractures attains its fully developed stage when the external load exceeds the peak(at post-90%，indicating that the load is at 90% of the peak in the post-peak regime)，with its length nearly twice as the length observed at the peak(17 mm vs. 9 mm). This study confirms that the fully developed stage of the I-type fracture process zone is directly correlated with the cohesive force model through experimental measurements of local acoustic emission.

Key words： rock mechanics fracture process zone(FPZ) acoustic emission(AE) mode I fracture full curve of FPZ development cohesive zone model

引用本文:

张艳1，2，林青2，3，高跃2，3，潘鹏志4. 砂岩I型断裂过程区全过程发育曲线的声发射簇类研究[J]. 岩石力学与工程学报, 2025, 44(5): 1257-1270.
ZHANG Yan1，2，LIN Qing2，3，GAO Yue2，3，PAN Pengzhi4. The full curve of the FPZ development in a mode I fracture of sandstone by acoustic emission(AE) cluster#br#. , 2025, 44(5): 1257-1270.

链接本文:

https://rockmech.whrsm.ac.cn/CN/10.3724/1000-6915.jrme.2024.0481 或 https://rockmech.whrsm.ac.cn/CN/Y2025/V44/I5/1257