Changes

The core is placed in a container filled with silicon and the strain is monitored (see [[:File:GeoWikiWriteOff2021-Tayyib-Figure17.png|Figure 17]]). The change in the core dimension is related to the microcracks creation in the rock when in-situ stress is relieved. The alignment of these micro fractures depends on the direction of the principal stresses. When the stress is relieved, the core tends to expand most in the maximum stress relief direction, and least in the minimum stress relief direction. The volume of the microcracks is proportional to the values of the in-situ stresses.  

The core is placed in a container filled with silicon and the strain is monitored (see [[:File:GeoWikiWriteOff2021-Tayyib-Figure17.png|Figure 17]]). The change in the core dimension is related to the microcracks creation in the rock when in-situ stress is relieved. The alignment of these micro fractures depends on the direction of the principal stresses. When the stress is relieved, the core tends to expand most in the maximum stress relief direction, and least in the minimum stress relief direction. The volume of the microcracks is proportional to the values of the in-situ stresses.  

[[File:GeoWikiWriteOff2021-Tayyib-Figure17.png|center|framed|{{Figure number|17}}Anelastic Strain Recovery Apparatus (ASR) (from Lin, W. et al. 2007) [13]]]

[[File:GeoWikiWriteOff2021-Tayyib-Figure17.png|center|framed|{{Figure number|17}}Anelastic Strain Recovery Apparatus (ASR; from Lin et al.<ref>Lin, W., E. Yeh, H. Ito, T. Hirono, W. Soh, C. Wang, K. Ma, J. Hung, and S. Song, 2007, Preliminary results of stress measurement using drill cores of TCDP hole-A: An application of anelastic strain recovery method to three-dimensional in-situ stress determination: Terrestrial, Atmospheric and Oceanic Sciences, v. 18, p. 379-393.</ref>]]

====Geological Method (Geologic Structure)====

====Geological Method (Geologic Structure)====

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13 Lin, W., Yeh, E., Ito, H., Hirono, T., Soh, W., Wang, C., Ma, K., Hung, J., & Song, S. (2007). Preliminary results of stress measurement using drill cores of TCDP hole-A: An application of anelastic strain recovery method to three-dimensional in-situ stress determination. Terrestrial, Atmospheric and Oceanic Sciences, v. 18, p. 379-393. doi:10.3319/TAO.2007.18.2.379(TCDP)

13  

14 Stacey, T., & Wesseloo, J., 1998, In situ stresses in mining areas in South Africa. South African Institute of Mining and Metallurgy, V. 98, P. 365-368.

14 Stacey, T., & Wesseloo, J., 1998, In situ stresses in mining areas in South Africa. South African Institute of Mining and Metallurgy, V. 98, P. 365-368.