Mesoscopic fatigue damage characteristics of reservoir bank slope sandstone under frequent microseisms

• Published in: Arabian journal of geosciences Vol. 15; no. 7
• Main Authors: Zhong, Zuliang, Wang, Qunli, Wang, Zhen, Liu, Xinrong, Zhou, Xiaohan
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.04.2022; Springer Nature B.V
• Subjects: Canyons; Cyclic loads; Damage; Deformation; Dynamic loads; Dynamic stability; Earth and Environmental Science; Earth science; Earth Sciences; Fatigue failure; Fatigue life; Imaging techniques; Load tests; Low speed; Magnetic resonance imaging; Materials fatigue; Mechanics; Medical imaging; Microcracks; Microseisms; NMR; Nuclear magnetic resonance; Original Paper; Porosity; Reservoirs; Resonance; Rocks; Sandstone; Sediment samples; Sedimentary rocks; Slope stability; Stability analysis; Stress; Working conditions; Cyclic dynamic load; Particle flow code (PFC); Mesoscopic damage; Sandstone; Nuclear magnetic resonance (NMR); Fatigue characteristics
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-022-09823-8

Microseisms have appeared frequently in the Three Gorges Reservoir Area since the record. For assessing the long-term stability of rock slopes subjected to repeated microseisms, through indoor cyclic dynamic load tests, combined with nuclear magnetic resonance technology and particle flow code (PFC), the damage mechanics characteristics and meso-damage evolution mechanism of sandstone subjected to cyclic loads were systematically studied. The research results show that when the upper limit stress exceeds the fatigue threshold, the rock samples’ fatigue life decreases as the upper limit stress and stress amplitude increase and increases when the loading frequency increases. Nuclear magnetic resonance (NMR) tests were performed on sandstone specimens at various loading times, and the porosity, T 2 spectra, and NMR imaging results under different working conditions were obtained. The findings of NMR studies revealed the development characteristics of microcracks in sandstone at three stages: initial deformation, low-speed deformation, and accelerated deformation. When comparing results of NMR and numerical experiments, it was discovered that the results obtained by the two methods were consistent in the progression of meso-damage, and numerical calculations further explained the reason for the uniform distribution of pores in magnetic resonance imaging (MRI).