Abstract:To investigate the degradation of rock microstructure under static and dynamic loads,split Hopkinson pressure bar(SHPB) tests of granite specimens with a pre-existing opening under various axial pre-stresses and the same dynamic load were conducted. The crosswise relaxation time T2 distribution,porosity and nuclear magnetic resonance images were obtained with the nuclear magnetic resonance(NMR) technique. The peak spectrum of T2,the spectral area and the porosity of the granite specimens subjected to the dynamic loading all increased with the increase of static axial pre-stress. The degradation of granite under static-dynamic loads was more sensitive when the static pre-stress exceeded 10 MPa. The NMR results of specimens with the circular opening and ones with the square opening were compared. The damage of the specimen with the square opening was severer than that with the circular opening,and this phenomenon was more pronounced when the static pre-stress exceeded 10 MPa. The NMR images yielded the straightforward demonstration of the damage degradation process of pore structure of granite under static-dynamic loads.
李夕兵,翁 磊,谢晓锋,吴秋红. 动静载荷作用下含孔洞硬岩损伤演化的核磁共振特性试验研究[J]. 岩石力学与工程学报, 2015, 34(10): 1985-1993.
LI Xibing,WENG Lei,XIE Xiaofeng,WU Qiuhong. STUDY ON THE DEGRADATION OF HARD ROCK WITH A PRE-EXISTING OPENING UNDER STATIC-DYNAMIC LOADINGS USING NUCLEAR MAGNETIC RESONANCE TECHNIQUE. , 2015, 34(10): 1985-1993.
MARTINI C D,READ R S,MARTINO J B. Observations of brittle failure around a circular test tunnel[J]. International Journal of Rock Mechanics and Mining Sciences,1997,34(7):1 065-1 073.
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