Experimental investigation on the mechanical behavior and fracture mechanism of sandstone after heat treatment

• Published in: Bulletin of engineering geology and the environment Vol. 83; no. 6; p. 220
• Main Authors: Zhang, Cheng, Wang, Fuzeng, Hu, Lingbao, Jiang, Feng, Huang, Guoqin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2024; Springer Nature B.V
• Subjects: Chemical properties; Chemicophysical properties; Crack propagation; Dynamic loads; Dynamic mechanical properties; Earth and Environmental Science; Earth Sciences; Electron microscopy; Engineering; Evaporation; Experimental methods; Experiments; Failure mechanisms; Failure modes; Foundations; Fracture mechanics; Geoecology/Natural Processes; Geoengineering; Geology; Geotechnical Engineering & Applied Earth Sciences; Heat treatment; Heat treatments; High temperature; Hydraulics; Immunoglobulins; Intergranular fracture; Mechanical properties; Mechanics; Nature Conservation; Original Paper; Physical properties; Porosity; Raman spectroscopy; Research methodology; Safety engineering; Sandstone; Scanning electron microscopy; Sedimentary rocks; Site selection; Spectroscopy; Spectrum analysis; Split Hopkinson pressure bars; Stone; Temperature; Tensile strength; Thermal decomposition; Thermal degradation; X-ray diffraction; Fracture mechanism; High-temperature; Sandstone; Physical and mechanical behavior
• ISSN: 1435-9529; 1435-9537
• DOI: 10.1007/s10064-024-03717-7

Rocks extracted from deep mining operations often undergo various complex temperature and dynamic load disturbances. In order to investigate the influence of temperature on the mechanical characteristics and fracture mechanisms of sandstone under different loading conditions, thermal treatments were conducted on sandstone samples at temperatures of 25 °C, 200 °C, 400 °C, 600 °C, 800 °C, and 1000 °C. Subsequently, the quasi-static and dynamic mechanical properties of the treated samples were tested and recorded using an electronic universal testing machine and a Split Hopkinson Pressure Bar (SHPB). Simultaneously, detailed analyses and discussions of thermal damage and failure mechanisms of the specimens were carried out using Energy-Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Raman spectroscopy. The results indicate that with increasing temperature, the mass, density, and peak stress of the sandstone specimens decrease, while the porosity and peak strain increase. Transgranular (TG) fracture was identified as the primary failure mode during loading, accompanied by a small amount of intergranular (IG) fracture. Furthermore, high temperatures cause changes in the chemical properties of the sandstone, resulting in thermal decomposition of crystal grains and evaporation of mineral components, which are key factors that weaken the mechanical properties of sandstone. The significance of this study is to provide theoretical and technical support for site selection and safety assessment of underground engineering projects.