Xu Shiang, Wang Shuangming, Zhang Pingsong, Yang Duoxing, Sun Binyang
State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, China.
School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China.
Sensors (Basel). 2020 Jul 10;20(14):3853. doi: 10.3390/s20143853.
A rock fracture test is a very important method in the study of rock mechanics. Based on the Mechanics Test System (MTS), the dynamic strain response of the failure process of cylindrical granite specimens under uniaxial compression was observed by using distributed optical fiber strain sensors. Two groups of tests were designed and studied for rock sample fracturing. The main comparison and analysis were made between the distributed optical fiber testing technology and the MTS testing system in terms of the circumferential strain response curve and the evolution characteristics of strain with time. The strain characterization of distributed optical fiber in the process of rock fracturing was obtained. The results show that the ring strains measured by the distributed optical fiber sensor and the circumferential strain gauge were consistent, with a minimum ring strain error of 1.27%. The relationship between the strain jump or gradient band of the distributed optical fiber and the crack space on the sample surface is clear, which can reasonably determine the time of crack initiation and propagation, point out the location of the rock failure area, and provide precursory information about rock fracture. The distributed optical fiber strain sensor can realize the linear and continuous measurement of rock mass deformation, which can provide some reference for the study of macro damage evolution and the fracture instability prediction of field engineering rock mass.
岩石断裂试验是岩石力学研究中非常重要的一种方法。基于力学试验系统（MTS），利用分布式光纤应变传感器观测了圆柱形花岗岩试件在单轴压缩下破坏过程中的动态应变响应。设计并研究了两组岩石样品破裂试验。主要从周向应变响应曲线以及应变随时间的演化特征方面，对分布式光纤测试技术与MTS测试系统进行了比较和分析。得到了岩石破裂过程中分布式光纤的应变特征。结果表明，分布式光纤传感器测得的环向应变与周向应变片测量结果一致，环向应变最小误差为1.27%。分布式光纤的应变突变或梯度带与样品表面裂纹间距的关系清晰，能够合理确定裂纹起裂和扩展时间，指出岩石破坏区域位置，并提供岩石断裂的前兆信息。分布式光纤应变传感器能够实现岩体变形的线性连续测量，可为现场工程岩体宏观损伤演化及断裂失稳预测研究提供一定参考。
