Ban Yuxin, Chen Lihong, Xie Qiang, Duan Jun, He Chunbo, Xue Xiaoqiang, Fu Xiang
School of Civil Engineering and Architecture, Chongqing University of Science and Technology, Chongqing, 401331, China.
School of Civil Engineering, Chongqing University, Chongqing, 400044, China.
Sci Rep. 2023 Jul 19;13(1):11639. doi: 10.1038/s41598-023-38285-5.
Natural defects, such as joints, structural surfaces and voids, significantly affect the mechanical properties and fracture modes of rock mass. Hidden fissures are widely distributed in magmatic rock, while their influences on the mechanical properties and the cracking mechanism are still unclear. Laboratory tests were conducted on prefabricating hidden-fissured rock-like specimens, as well as intact specimens and close-fissured specimens as a comparison. The real-time digital image correlation technology and acoustic emission monitoring technology were synchronously adopted to capture both the external and internal cracking process. The results show that the hidden fissures can weaken the uniaxial compression strength, while the deterioration effect of hidden fissures is weaker than closed fissures due to the internal cohesion among fissure internal particles. What's more, the initiation behavior of the α = 90° hidden-fissured specimen is different from that of β = 90° closed-fissured specimen. Finally, the cracking mechanism of hidden-fissured specimens was revealed by analyzing the RA-AF relationship. The failure of the close-fissured specimens is mainly the tensile-shear mixed fracture mode, while the failure of the hidden-fissured specimens is mainly the tensile fracture mode and supplemented by the shear. The experimental results contribute to the understanding of cracking properties in hidden-fissured rock.
诸如节理、结构面和孔洞等天然缺陷会显著影响岩体的力学性能和断裂模式。隐裂隙广泛分布于岩浆岩中，但其对力学性能及开裂机制的影响尚不清楚。对预制隐裂隙类岩石试件进行了室内试验，并以完整试件和闭合裂隙试件作为对比。同步采用实时数字图像相关技术和声发射监测技术来捕捉外部和内部的开裂过程。结果表明，隐裂隙会削弱单轴抗压强度，而由于裂隙内部颗粒间的内聚力，隐裂隙的劣化作用比闭合裂隙弱。此外，α = 90°隐裂隙试件的起裂行为与β = 90°闭合裂隙试件不同。最后，通过分析RA - AF关系揭示了隐裂隙试件的开裂机制。闭合裂隙试件的破坏主要是拉剪混合断裂模式，而隐裂隙试件的破坏主要是拉伸断裂模式并辅以剪切。试验结果有助于理解隐裂隙岩石的开裂特性。
