Assessments of the disintegrating behaviour of clay shale considering the effect of pH condition

Abstract

In this paper, several disintegration tests were conducted in different acid and alkali solutions and their results were analysed. A theoretical model based on the principle of similarity and the conservation of mass were proposed to describe the relationship between the number of disintegration cycles and the particle size distributions. Using this model, the fractal evolution of the disintegration of clay shales under different pH conditions were evaluated and the results show that the fractal dimension of clay shale disintegration is greater at initial cycles in acidic solutions compared with that in alkaline solutions, All fractal dimensions, however, approach the same value given enough number of disintegration cycles but more cycles are needed in alkaline solutions for the value of fractal dimension to become stable. Another theoretical model was also proposed in this paper to evaluate the incremental surface energy and cumulative incremental surface energy of clay shale disintegration based on the principle of energy dissipation. And the relationships between the cumulative incremental surface energy and the pH value were obtained for the case study. It was found that all curves have the same attenuation trend, and the absolute incremental surface energy decreases as the disintegration cycle increases.

Keywords:

• Soft rock
• disintegration characteristics
• fractal theory
• energy dissipation
• pH value