Strength, Deformability and X-ray Micro-CT Observations of Deeply Buried Marble Under Different Confining Pressures
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- 作者：Sheng-Qi Yang ; Yang Ju ; Feng Gao ; Yi-Lin Gui
- 关键词：Deeply buried marble ; Strength ; Brittle–ductile transition ; X ; ray micro ; CT ; Crack
- 刊名：Rock Mechanics and Rock Engineering
- 出版年：2016
- 出版时间：November 2016
- 年：2016
- 卷：49
- 期：11
- 页码：4227-4244
- 全文大小：9,555 KB
- 刊物类别：Earth and Environmental Science
- 刊物主题：Earth sciences
Geophysics and Geodesy
Civil Engineering - 出版者：Springer Wien
- ISSN：1434-453X
- 卷排序：49
文摘
In this research, a series of triaxial compression experiments and X-ray observations were conducted to explore the strength, deformability and internal damage mechanism of deeply buried marble. The results show that an increase in confining pressure results in obvious brittle–ductile transition characteristics of deeply buried marble. The Young’s modulus of the marble increased nonlinearly with increasing confining pressure. The peak and residual strength of the marble exhibit a clear linear relationship with the confining pressure, which can be described by the linear Mohr–Coulomb criterion. The sensitivity of the residual strength on the confining pressure was clearly higher than that of the peak strength. After uniaxial and triaxial compression failure, marble specimens were analyzed using a three-dimensional X-ray micro-CT scanning system. Based on horizontal and vertical cross-sections, the marble specimen is mainly dominated by axial splitting tensile cracks under uniaxial compression, but under confining pressure, the marble specimen is mainly dominated by a single shear crack. To quantitatively evaluate the internal damage of the marble material, the crack area and aperture extent for each horizontal cross-section were calculated by analyzing the binarized pictures. The system of crack planes under uniaxial compression is more complicated than that under triaxial compression, which is also supported by the evolution of the crack area and aperture extent. Finally, the brittle–ductile transition mechanism of the marble is discussed and interpreted according to the proposed conceptual models.