Disintegration characteristics and mechanism of red-bed argillaceous siltstone under drying–wetting cycle

• Published in: Environmental earth sciences Vol. 81; no. 12
• Main Authors: Huang, Kai, Kang, Bo, Zha, Fusheng, Li, Yunfeng, Zhang, Qing, Chu, Chengfu
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2022; Springer Nature B.V
• Subjects: Biogeosciences; Cycles; Dimensions; Disintegration; Drawdown; Drying; Earth and Environmental Science; Earth science; Earth Sciences; Energy dissipation; Energy exchange; Engineering; Environmental Science and Engineering; Experiments; Fractal geometry; Fractals; Fractures; Geochemistry; Geology; Hydrology/Water Resources; Laboratories; Microstructural analysis; Minerals; Original Article; Rivers; Siltstone; Surface energy; Surface properties; Terrestrial Pollution; Water diversion; Water softening; Wetting; Fractal theory; Disintegration mechanism; Energy dissipation; Drying–wetting cycles; Red-bed argillaceous siltstone
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-022-10450-5

Red-bed argillaceous siltstone is a common soft rock in the drawdown area of water diversion project extending from the Yangtze to Huaihe Rivers, with the characteristics of water softening and disintegration, which directly threatens the stability and safety of the diversion project. To better understand the effect of cyclic drying–wetting on the disintegration characteristics and mechanism, disintegration experiments were conducted on the red-bed argillaceous siltstone from the Tongcheng area of the water diversion project extending from the Yangtze to Huaihe Rivers. Experimental results indicated that, with an increasing number of drying–wetting cycles, the red-bed argillaceous siltstone was gradually crushed, large particles gradually transformed into small particles. A microstructural analysis showed that a continuous drying–wetting process resulted in the sample surface becoming disordered and complicated, and new micro-fractures and pores were generated. Notable changes in the concentrations of ions in the soaking solutions indicated continuous dissolution of the minerals, and a large amount of mineral loss under the action of cyclic drying–wetting. Furthermore, the evolution of disintegration parameter further indicated that the disintegration of red-bed argillaceous siltstone was gradually intensified by the increasing number of drying–wetting cycles. The fractal dimension D and the incremental surface energy gradually increased with an increase in the number of drying–wetting cycles. Thus, the proposed energy dissipation model effectively describes the disintegration characteristics of red-bed argillaceous siltstone under the cyclic drying–wetting, and thus, it can be used to guide engineering practices.