Compressive failure characteristics of yellow sandstone subjected to the coupling effects of chemical corrosion and repeated freezing and thawing

摘要

AbstractThe coupling effects of chemical corrosion and freeze-thaw (F-T) cycling on the compressive failure characteristics of yellow sandstone were investigated. Results show that both chemical corrosion and minimum temperature in F-T cycles have adverse effect on the mechanical properties of yellow sandstone. With decreasing minimum F-T temperature and pH of the corrosive solution, peak stress and elastic modulus both decrease while peak strain increases, illustrating that the bearing capacity and deformation resistant capacity both decrease while ductility increases. During UCS tests, less damaged samples with a lower porosity tend to exhibit double-cone failure and contain smaller pores and more trans-grain fractures. Higher-damage samples with higher porosity tend to exhibit split failure or slope failure and contain larger pores and more inter-grain fractures. Chemical reactions between yellow sandstone and various chemical solutions are analyzed. F-T damage primarily occurs during freezing while chemical corrosion primarily occurs during thawing. Additionally, both the friction state and the internal microstructural damage influence the final failure mode. Results of this work can provide reference for the construction and development of rock structures in cold regions.Highlights?The coupled effect of chemical corrosion and F-T cycling on sandstone are studied.?Possible chemical reactions are analyzed to explain this coupling effect.?Failure modes of UCS tests are from three basic patterns or their combinations.?SEM is adopted to analyze the micro-structure of the samples.?Internal micro-structures and frictional states both affect the final failure modes.]]>