关键词: 酸腐蚀, 声发射, 腐蚀机制, 能量演化, 分形维数

Abstract: By means of uniaxial compression test, acoustic emission (AE) monitoring approach and X-ray diffraction technique, we analyzed the mechanical properties of granite at different corrosion times and obtained the variation law of AE characteristic parameters. The causes of internal structure deterioration of granite were analyzed from the perspective of corrosion mechanism, and the energy evolution law and fractal characteristics of fragmentation during the destruction of rock samples were investigated. The test results showed that with the increase of corrosion time, the uniaxial compressive strength and elastic modulus decrease by 25.6% and 38.3%, respectively. The cumulative AE ring count is reduced, and the duration of high-level AE ring count is shortened. The internal structure of the rock sample deteriorates due to the decomposition of mineral components, and the silica suspension delays this deterioration, resulting in a negative correlation between the reduction rate of mechanical parameters and the corrosion time. Before the plastic stage, the growth rate of dissipated energy of corroded rock sample is large, its internal damage has developed rapidly, and the dissipated energy is also at a high level. At the plastic stage, the degree of damage development is lower than that of non-corroded rock sample. The dissipated energy decreases with the increase of corrosion time, but the proportion of dissipated energy increases from 29.1% to 35.0%, and the ductility increases. The peak value and growth rate of total energy and elastic strain energy decrease with the increase of corrosion time, the deterioration degree of internal structure increases, and the energy absorption capacity and energy storage limit of rock samples decrease. The failure mode changes from shear splitting failure to shear failure. The mass proportion of medium and small particle size fragments is reduced from 44.6% to 22.8%, the fractal dimension of fragmentation is reduced by 9.5%, the degree of fragmentation is reduced, and the dissipated energy for fragmentation is also reduced.

Key words: acid corrosion, acoustic emission (AE), corrosion mechanism, energy evolution, fractal dimension