| Autor: |
Shi, Zhanming, Li, Jiangteng, Pathegama Gamage, Ranjith, Wang, Mengxiang, Lin, Hang, Xie, Shijie |
| Předmět: |
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| Zdroj: |
Rock Mechanics & Rock Engineering; Dec2024, Vol. 57 Issue 12, p10245-10263, 19p |
| Abstrakt: |
To improve the mining efficiency of geothermal energy, this paper designed a mode II fracture test of double-edge notched cube granite samples after a thermal shock to study the shear fracture characteristics of hot dry rocks. First, the effects of temperature and normal stress on the shear parameters such as shear strength, cohesion, and internal friction angle of the specimens were analyzed. Then, the evolution of the specimens' morphology parameters such as fractal dimension and joint roughness coefficient were investigated. Finally, a multi-scale analysis of the differences between shear and morphology parameters was conducted based on thermogravimetric analysis and scanning electron microscope technology. The results show that the specimens' shear and morphology parameters have a quadratic function relationship with temperature and a linear positive correlation with normal stress. The threshold temperature of samples is 256.36 °C. When the thermal shock temperature is lower than the threshold temperature, the shear parameters strengthen and the morphology parameters decrease. Conversely, the shear parameters weaken, and the morphology parameter increases. The height of the bulges on the shear surface increases along the shear direction, resulting in an obvious climbing phenomenon. The mode II fracture characteristics of the samples can be described using the dislocation slip theory and rock bridge weakening mechanic model. The area of scratches on the shear surface can be used as a macroscopic representation of the morphology parameters. Water evaporation/separation and mineral dehydration/phase transition inside the granite samples are the main reasons for the differences between shear and morphology parameters. Highlights: Mode II fracture test on double-edge notched cube granite after thermal shock. Thermogravimetric technology is used to determine the threshold temperature. There is a climbing phenomenon along the shear direction on the shear surface. The samples' fracture characteristics obey rock bridge weakening mechanic model. Scratch can be used as a macroscopic representation of the morphology parameters. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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