工程地质学报2024，Vol.32Issue(3)：840-850,11.DOI:10.13544/j.cnki.jeg.2023-0263
冻融雁行裂隙花岗岩单轴压缩宏细观疲劳特性试验研究
EXPERIMENTAL STUDY ON MACRO-MICRO FATIGUE CHARACTERIS-TICS OF FREEZE-THAW DOUBLE-FISSURED GRANITE UNDER UNIAXI-AL COMPRESSION
摘要
Abstract
For rock mass engineering in frozen areas,rocks are often subjected to coupling fatigue damage caused by freeze-thaw cycles and periodic load disturbances.To study the fatigue cracking propagation of freeze-thaw frac-tured granite and quantify the degree of damage and classification types of cracks,three periodic load tests under stress amplitude were conducted on double-fractured granite after 40 freeze-thaw cycles.Real-time acoustic emission and high-speed photographic monitoring technology were employed to reveal crack evolution,and different crack cracking types were further classified to aid in understanding dynamic fracturing laws.Additionally,the relationship between mesoscopic pore characteristics and macroscopic mechanical properties of fractured granite was analyzed through nuclear magnetic resonance testing.The results demonstrate that with the increase in amplitude-stress ratio of the periodic load,the double-fractured granite experiences a"silent period"during the periodic load.The pro-portion of shear cracks generated by double-fractured granite during periodic loading stages is greater than that dur-ing monotonic loading stages,and the rock is prone to forming shear failure cracks under high amplitudes.Further-more,the maximum value of acoustic emission from double-fractured granite decreases,indicating a decrease in large-scale fractures.Additionally,the angle of the extended crack to the end face of the outer tip of the prefabrica-ted fracture of the rock sample is larger under periodic load.The fatigue life of double-fractured granite decreases,the development of internal microfracture propagation slows down,and the H-containing fluid that can be stored is also reduced,ultimately manifested as a decrease in the area change rate of the nuclear magnetic resonance T2 spectral area.关键词
冻融循环/双裂隙花岗岩/振幅应力比/疲劳损伤/裂纹开裂模式Key words
Freeze-thaw cycle/Double fissure granite/Amplitude-stress ratio/Fatigue damage/Crack cracking mode分类
天文与地球科学引用本文复制引用
任建喜,杨淏冰,谢易,张犇,焦金照..冻融雁行裂隙花岗岩单轴压缩宏细观疲劳特性试验研究[J].工程地质学报,2024,32(3):840-850,11.基金项目
国家自然科学基金项目(资助号:12072259).This research is supported by the National Natural Science Foundation of China(Grant No.12072259). （资助号:12072259）
