College of Urban Construction, Yangtze University
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences

为探究软硬互层岩石在破坏后的损伤演化规律，利用相似模型理论制作3组类岩石试块（软岩、互层岩石、硬岩），在对类岩石试块进行单轴压缩的同时辅以压电陶瓷试验和数字图像相关技术（digital image correlation,以下简称DIC）来实时检测岩石的内外损伤，分析其破坏状态和损伤演化规律。试验结果表明：软硬互层岩石的强度、变形特性介于类软岩、类硬岩之间，在达到峰值点前其力学规律类似于软岩有一定的膨胀变形，而在破坏后其力学特性为接近硬岩的脆性破坏；将压电陶瓷时域信号和DIC应变图像与岩石从加载至破坏的过程相结合，发现各类岩石呈现初始平缓、中期加速、末期减缓的“S”形损伤演化规律；压电陶瓷时域信号的衰减幅度与岩石损伤中前期过程正相关，而DIC图像应变变化特征与岩石损伤中后期过程关联密切；软硬互层岩石损伤中前期过程主要是软岩部分的变形及硬岩部分少量的裂纹发育导致的损伤累积变化，而后期则主要是硬岩部分微裂纹相互连接贯通导致的损伤累积，最终表现为软岩部分的粉碎、硬岩部分呈现明显的贯通裂纹。结合压电陶瓷与DIC技术的损伤监测特点，基于尖点突变理论量化岩石损伤曲线中的突变区间和突变交点，以突变交点为岩石内外损伤的分段点，提出内外损伤结合的岩石本构模型。

In order to explore the damage evolution law of soft and hard interbedded rock after failure, three groups of rock-like test blocks (soft rock, interbedded rock and hard rock) were made by using the similar model theory. In addition to uniaxial compression of rock-like test blocks, piezoelectric ceramic test and digital image correlation (DIC) technology are used to detect rock internal and external damages in real time, and analyze its failure state and damage evolution law. The test results show that the strength and deformation characteristics of soft and hard interbedded rock are between those of soft and hard rock. Before reaching the peak point, the mechanical law is similar to that of soft rock with certain expansion deformation, but after failure, the mechanical property is similar to that of hard rock with brittle failure. By combining the time domain signal of piezoelectric ceramics and DIC strain images with the process of rock loading to failure, it is found that all kinds of rocks present an “S” shaped damage evolution law, which is gentle at the beginning, accelerated at the middle stage and slowed down at the end. The time domain signal attenuation amplitude of piezoelectric ceramics is positively correlated with the early stage of rock damage, while the strain variation characteristics of DIC images are closely correlated with the middle and late stage of rock damage. In the early stage, the damage accumulation is mainly caused by the deformation of the soft rock and the development of a small number of cracks in the hard rock, while in the late stage, the damage accumulation is mainly caused by the interconnecting and transfixating of microcracks in the hard rock. The damage accumulation is finally manifested as the crushing of the soft rock and the obvious transfixating cracks in the hard rock. Combined with the damage monitoring characteristics of piezoelectric ceramics and DIC technology, the abrupt change interval and abrupt change intersection in rock damage curves were quantified based on the abrupt change theory, and the abrupt change intersection was taken as the subsection point of rock internal and external damage. A rock constitutive model combining internal and external damage was proposed.

湖北省自然科学基金资助项目（2020CFB367）

亓宪寅，柯婷，耿殿栋. 基于压电陶瓷和DIC的软硬互层岩石内外损伤试验及模型研究[J]. 煤矿安全，2023，54（9）：119−128

QI Xianyin, KE Ting, GENG Diandong. Damage test and model study of soft and hard interbedded rock based on piezoelectric ceramics and DIC[J]. Safety in Coal Mines, 2023, 54（9）: 119−128