Dynamic Characteristics of Sandstone under Coupled Static-Dynamic Loads after Freeze-Thaw Cycles

• Published in: Applied sciences Vol. 10; no. 10; p. 3351
• Main Authors: Ke, Bo, Zhang, Jian, Deng, Hongwei, Yang, Xiangru
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.05.2020
• Subjects: Absorption; Axial stress; Civil engineering; Cold; Compression; Densification; Dynamic characteristics; Dynamic loads; Dynamic mechanical properties; Earthquakes; Energy absorption; failure mode; Failure modes; freeze-thaw cycles; Freeze-thawing; Load; Mechanical properties; Mechanics; Microstructure; Natural history; NMR; Nuclear magnetic resonance; Observations; rock dynamic mechanics; Rocks; Sandstone; split Hopkinson Pressure Bar; Static loads; static-dynamic loads; Stone; Storage modulus; Strain; Stress; Stresses (Materials); Studies; Temperature effects; Thermal properties; Tomography; China
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app10103351

The effect of temperature fluctuation on rocks needs to be considered in many civil engineering applications. Up to date the dynamic characteristics of rock under freeze-thaw cycles are still not quite clearly understood. In this study, the dynamic mechanical properties of sandstone under pre-compression stress and freeze-thaw cycles were investigated. At the same number of freeze-thaw cycles, with increasing axial pre-compression stress, the dynamic Young’s modulus and peak stress first increase and then decrease, whereas the dynamic peak strain first decreases and then increases. At the same pre-compression stress, with increasing number of freeze-thaw cycles, the peak stress decreases while the peak strain increases, and the peak strain and peak stress show an inverse correlation before or after the pre-compression stress reaches the densification load of the static stress–strain curve. The peak stress and strain both increase under the static load near the yielding stage threshold of the static stress–strain curve. The failure mode is mainly shear failure, and with increasing axial pre-compression stress, the degree of shear failure increases, the energy absorption rate of the specimen increases first and then decreases. With increasing number of freeze-thaw cycles, the number of fragments increases and the size diminishes, and the energy absorption rates of the sandstone increase.