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Damage Evolution During Rock Pulverization Induced by Dynamic Compressive Loading
Author(s) -
Yao W.,
Xu Y.,
Xia K.
Publication year - 2020
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2020jb019388
Subject(s) - split hopkinson pressure bar , dynamic loading , compression (physics) , dynamic range compression , geology , strain rate , shear (geology) , geotechnical engineering , dynamic load testing , fault (geology) , strain (injury) , bar (unit) , materials science , fracture (geology) , composite material , seismology , medicine , oceanography
Rock pulverization is a geological process in which fault zone rocks are shattered in situ, into fine grains much smaller than the original grain size, without significant shear strain. Investigations regarding the genesis of pulverized fault zone rock (PFZR) suggested that it is a coseismic phenomenon and may be closely associated with supershear earthquakes. The observation of dynamic damage evolution is thus significant for understanding the rock pulverization mechanism due to dynamic compressive load. In this study, the damage evolution of Laurentian granite under dynamic compression loading is studied by using the strain control technique in a split Hopkinson pressure bar system. Dynamic compression experiments are performed under different maximum strain levels and different loading rates. Tested specimens are recovered for postmortem examination with X‐ray micro‐computed tomography and microscopic observation. 3‐D microcrack networks due to different dynamic loading rates are examined, and the evolution of the crack volume and crack number at various loading rates are analyzed. The results reveal that the pulverization process during dynamic compression loading is categorized into three stages. Both a high loading rate and a sufficient strain are necessary for the rock pulverization to occur. The main features of fractures during rock pulverization are discussed, and the total dissipated energy for dynamic fracture and pulverization is quantified.