Abstract
The physicomechanical deterioration characteristics of sandstone subjected to H2SO4, HCl, and H2O solutions of different pH values are studied by the method of long-term accelerated immersion. The quantitative relationships between the damage variables based on CT (computer tomographic identification technology) numbers and the immersion time, the uniaxial compressive strength, the peak point strain, and the elastic modulus of rock samples are analyzed. The test results indicate that the pH value of immersion solutions, the dissolution rate of Ca2+ and Na+, and the quality change of rock samples show visible stage characteristics under acidic environment. With the soaking time extended, the pH value of solutions increases gradually, and the quality change of rock samples decreases gradually. The smaller the pH value of immersion solutions is, the higher the dissolution rate of Ca2+ and Na+ is. However, the cation dissolution rate under a weak acid environment with a high pH value has little difference with that under the distilled water (pH = 7). With the increase of the soaking time and the acidity, the compaction stage of rock samples becomes longer, the elastic stage becomes shorter, the deterioration degree of mechanical parameters becomes more extensive, and the destruction of sandstone samples shows ductility characteristics increasingly. The corrosion degree of corroded sandstone samples is quantitatively represented by microscopic damage variables based on CT numbers. The regression analysis results show that damage variables of acid-corroded sandstone samples have a power function relationship with soaking time and an exponential function relationship with peak strength, peak point strain, and elastic modulus.
Highlights
E physicomechanical deterioration characteristics of sandstone subjected to H2SO4, HCl, and H2O solutions of different pH values are studied by the method of long-term accelerated immersion. e quantitative relationships between the damage variables based on Computer tomographic identification technology (CT) numbers and the immersion time, the uniaxial compressive strength, the peak point strain, and the elastic modulus of rock samples are analyzed. e test results indicate that the pH value of immersion solutions, the dissolution rate of Ca2+ and Na+, and the quality change of rock samples show visible stage characteristics under acidic environment
With the increase of the soaking time and the acidity, the compaction stage of rock samples becomes longer, the elastic stage becomes shorter, the deterioration degree of mechanical parameters becomes more extensive, and the destruction of sandstone samples shows ductility characteristics increasingly. e corrosion degree of corroded sandstone samples is quantitatively represented by microscopic damage variables based on CT numbers. e regression analysis results show that damage variables of acid-corroded sandstone samples have a power function relationship with soaking time and an exponential function relationship with peak strength, peak point strain, and elastic modulus
Wang et al [21, 22] and Han et al [23] had studied the effect of chemical solution soaking on the mechanical properties of sandstone and sand slate by uniaxial and triaxial compression tests. ey found that the mechanical properties of sandstone decrease obviously after chemical corrosion, and it is closely related to the change of porosity. e conclusion that the elastic modulus and compressive strength of rocks decrease with the increase of soaking time and acidity was drawn
Summary
Academic Editor: Timo Saksala e physicomechanical deterioration characteristics of sandstone subjected to H2SO4, HCl, and H2O solutions of different pH values are studied by the method of long-term accelerated immersion. e quantitative relationships between the damage variables based on CT (computer tomographic identification technology) numbers and the immersion time, the uniaxial compressive strength, the peak point strain, and the elastic modulus of rock samples are analyzed. e test results indicate that the pH value of immersion solutions, the dissolution rate of Ca2+ and Na+, and the quality change of rock samples show visible stage characteristics under acidic environment. E quantitative relationships between the damage variables based on CT (computer tomographic identification technology) numbers and the immersion time, the uniaxial compressive strength, the peak point strain, and the elastic modulus of rock samples are analyzed. Huo et al [9,10,11,12] and Li et al [13, 14] obtained the evolution laws of physical, chemical, and mechanical properties of acid corrosion sandstone and mortar by the indoor long-term accelerated corrosion test under acidic environment, established the constitutive model of sandstone in acid solutions, deduced the damage variables of acid corrosion sandstone based on CT numbers, and revealed the corrosion mechanism of sandstone under acidic environment. E conclusion that the elastic modulus and compressive strength of rocks decrease with the increase of soaking time and acidity was drawn He and Guo [24] studied the failure of rock strength affected by different acid solutions from macroscopic and microscopic perspectives through core tests. The common sandstone in water conservancy and civil engineering is taken as the research object. e physical and mechanical properties of sandstone under acidic environment are systematically studied based on the uniaxial compression test. e quantitative relationship between damage variables and soaking time and mechanical parameters is established, which provides a basis for quantifying the deterioration degree of rocks in the acid environment
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