Nuclear magnetic resonance (NMR) and damage impact testing, using a split Hopkinson pressure bar (SHPB) technique, were\nconducted on weakly weathered granites of different porosities. Based on this, this study determined and analysed the pore\nstructure and distribution, propagation characteristics of stress waves, changes in initial tangent modulus, and energy dissipation\nin weakly weathered granites of different porosities. The research demonstrated that the nature of the internal porosity of weakly\nweathered granites changed with total porosity. Pore structure significantly influenced the amplitude of reflected waves and\ndistortion of transmitted waves. Under constant-damage impact loads, the initial tangent modulus decreased with increasing\nporosity, whereas the stress-strain curves, after reaching the peak stress, had similar shapes. Peak stress and average strain rate\nshowed a strong power-law correlation with porosity, and peak stress decreased in a power-law correlation with the increase of\naverage strain rate. In other words, the difference in average strain resulted from different porosities when the incident energy was\nsame, and the average strain was negatively correlated with porosity. Under damaging impact, the energy absorbed per unit\nvolume decreased with increasing porosity. The research results reveal dynamic characteristics of natural porous rocks under\ndamage impacts, which provide a reference for studying damage effects of porous rocks under the effects of stress waves
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