DISINTEGRATION ENERGY DISSIPATION MODEL OF WULONG FORMATION SANDSTONE IN CRETACEOUS UNDER HYDROCHEMICAL ENVIRONMENT

The sandstone of the Cretaceous Wulong Formation is highly susceptible to erosion and disintegration in hydrochemical environments due to its young age,relatively short deposition time,and incomplete internal cementation,leading to various disasters. This study focuses on the cyclic disintegration test of the Cretaceous Wulong Formation sandstone in chemical solutions with different acidity and alkalinity. The disintegration resistance index of the rock during the disintegration process under the action of hydrochemistry was analyzed through experiments. After each disintegration cycle,the mass percentage of disintegration in each particle size range was obtained to analyze the disintegration characteristics of the Wulong Formation sandstone in a hydrochemical environment. Microscopic observation and detection methods,including X-ray diffraction and scanning electron microscope tests,were employed to explore changes in mineral components before and after disintegration,as well as the microscopic characteristics of the rock during disintegration. A mathematical model of energy dissipation,reflecting the disintegration process based on thermodynamics and fracture mechanics theories,was constructed. The research results indicate that the overall disintegration rate of the Cretaceous Wulong Formation sandstone increases initially and then decreases,eventually stabilizing. The disintegration intensity of the Wulong Formation sandstone exhibits a differentiated characteristic of acid>alkaline>neutral. The disintegration particle gradation distribution data and micro-geometric structure parameters under different disintegration cycles were incorporated into the energy dissipation model. The analysis demonstrates that the energy dissipation model of rock disintegration can effectively characterize the disintegration process. These findings can serve as a reference for studying the mechanism of rock disintegration.