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Keywords: weak sandstone, digital image correlation, plastic strain, microscopic mechanism.

Summary

Weak sandstones possess deformational behaviours different from hard rocks, and these phenomena, including large amount of nonlinear deformation and softening of deformational modulus, are much more significant [1,2,3].

From the micro-point of view, the deformation or fracture of weak sandstones, when subjected to external loading, has been an interesting and important issue for researchers. However, how to effectively measure the strain field using micro-vision becomes increasingly necessary to gain more insight into the deformation behaviour of weak sandstones.

The digital image correlation method (DIC) is the latest optical measuring technique, which provides an effective and high precision strain distribution for a field. Therefore, using the DIC method, this paper firstly observes the deformation patterns and the fracture propagation of weak sandstone under uniaxial loading. Afterward, the microscopic mechanism that accounts for the significant deformation is further explored.

According to the analysis results of this study, the deformation of weak sandstone possesses the following characteristics:

Weak sandstone exhibits a non-uniform strain pattern under loading, and the matrix portion is relatively softer than the grain.
The plastic deformation mostly accumulates in the matrix portion.
When the stress approaches the ultimate strength, the fracture propagation can be identified using the DIC method.
Deducing from the stress-strain curves, the modulus of each element can be obtained, and the modulus of the grains are higher than that of the matrix.

References

1: F.S. Jeng, M.C. Weng, M.L. Lin, T.H. Huang, "Influence of Petrographic Parameters on Geotechnical Properties of Tertiary Sandstones from Taiwan", Engineering Geology, 73, 71-91, 2004. doi:10.1016/j.enggeo.2003.12.001
2: F.S. Jeng, M.L. Lin, T.H. Huang, "Study of the Geological Barriers of the Tunnels in Northern Taiwan (in Chinese)", Ministry of Transportation, Research Report, Taipei, Taiwan, 1996.
3: M.C. Weng, F.S. Jeng, T.H. Huang, M.L. Lin, "Characterizing the Deformation Behavior of Tertiary Sandstones", International Journal of Rock Mechanics and Mining Science, 42, 388-401, 2005. doi:10.1016/j.ijrmms.2004.12.004

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 89 PROCEEDINGS OF THE SIXTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY Edited by: M. Papadrakakis and B.H.V. Topping Paper 165 Characterizing the Deformation Behavior of Weak Sandstone from Micro-Vision M.C. Weng¹, S.H. Tung¹, M.H. Shih², C.C. Yu¹ and Y.T. Huang¹ ¹Department of Civil and Environmental Engineering, National University of Kaohsiung, Taiwan ²Department of Construction Engineering, National Kaohsiung First University of Science and Technology, Taiwan doi:10.4203/ccp.89.165 purchase the full-text of this paper Full Bibliographic Reference for this paper M.C. Weng, S.H. Tung, M.H. Shih, C.C. Yu, Y.T. Huang, "Characterizing the Deformation Behavior of Weak Sandstone from Micro-Vision", in M. Papadrakakis, B.H.V. Topping, (Editors), "Proceedings of the Sixth International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 165, 2008. doi:10.4203/ccp.89.165 Keywords: weak sandstone, digital image correlation, plastic strain, microscopic mechanism. Summary Weak sandstones possess deformational behaviours different from hard rocks, and these phenomena, including large amount of nonlinear deformation and softening of deformational modulus, are much more significant [1,2,3]. From the micro-point of view, the deformation or fracture of weak sandstones, when subjected to external loading, has been an interesting and important issue for researchers. However, how to effectively measure the strain field using micro-vision becomes increasingly necessary to gain more insight into the deformation behaviour of weak sandstones. The digital image correlation method (DIC) is the latest optical measuring technique, which provides an effective and high precision strain distribution for a field. Therefore, using the DIC method, this paper firstly observes the deformation patterns and the fracture propagation of weak sandstone under uniaxial loading. Afterward, the microscopic mechanism that accounts for the significant deformation is further explored. According to the analysis results of this study, the deformation of weak sandstone possesses the following characteristics: Weak sandstone exhibits a non-uniform strain pattern under loading, and the matrix portion is relatively softer than the grain. The plastic deformation mostly accumulates in the matrix portion. When the stress approaches the ultimate strength, the fracture propagation can be identified using the DIC method. Deducing from the stress-strain curves, the modulus of each element can be obtained, and the modulus of the grains are higher than that of the matrix. References 1 F.S. Jeng, M.C. Weng, M.L. Lin, T.H. Huang, "Influence of Petrographic Parameters on Geotechnical Properties of Tertiary Sandstones from Taiwan", Engineering Geology, 73, 71-91, 2004. doi:10.1016/j.enggeo.2003.12.001 2 F.S. Jeng, M.L. Lin, T.H. Huang, "Study of the Geological Barriers of the Tunnels in Northern Taiwan (in Chinese)", Ministry of Transportation, Research Report, Taipei, Taiwan, 1996. 3 M.C. Weng, F.S. Jeng, T.H. Huang, M.L. Lin, "Characterizing the Deformation Behavior of Tertiary Sandstones", International Journal of Rock Mechanics and Mining Science, 42, 388-401, 2005. doi:10.1016/j.ijrmms.2004.12.004 purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £95 +P&P)
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