Nonlinear analysis of argillaceous slate disintegration under water–rock effects

Argillaceous slate exhibits distinct disintegration characteristics during the interaction between water and rock. To investigate the disintegration of argillaceous slate, its macroscopic disintegration characteristics were examined through disintegration resistance tests. The mineral types and contents of the rock samples were determined using X-ray diffraction, while microstructural evolution during disintegration was analyzed via scanning electron microscopy. Nuclear magnetic resonance was employed to explore the mesoscopic mechanisms of argillaceous slate disintegration. A nonlinear dynamic equation was formulated based on nonlinear dynamics theory to quantitatively characterize the disintegration process of argillaceous slates under water-rock interaction. The results indicate that: 1) The disintegration process of argillaceous slate exhibits staged characteristics, with crack development categorized into three distinct stages. 2) During disintegration, the microstructure of argillaceous slate transitions to a more porous and loose state, as evidenced by the detachment of local flakes from the sample, the accumulation of flakes on the surface, and the formation of numerous pores. As the duration of water immersion increases, the internal pore radius of the argillaceous slate expands, leading to a continuous increase in the proportion of larger-sized pores. 3) The micro-scale fracture surface area of argillaceous slate increases with prolonged soaking time and shows a negative correlation with the anti-disintegration index. 4) Predictions derived from the nonlinear kinetic equation align well with the experimental data, demonstrating the equation's effectiveness in modeling the disintegration of argillaceous slates under the nonlinear quantification of water-rock interactions. The research results can provide a reference for the research and treatment of soft rock disintegration.