Introduction
Regional geology
Methodology
Detailed petrographic investigations
Rock types | Sample. no. | Qz | Bt | Ms | Pl | Afs | Amp | Grt | Ep | Chl | Cal |
---|---|---|---|---|---|---|---|---|---|---|---|
Granitic gneiss | S1 | 44 | 15 | 15 | 5 | 20 | – | – | ~ 1 | – | – |
S2 | 36 | 20 | 17 | 21 | 6 | – | < 1 | – | – | ||
S4 | 35 | 4 | 24 | 13 | 20 | – | < 1 | ~ 1 | – | – | |
S5 | 56 | 2 | 7 | 10 | 25 | – | – | – | – | – | |
S6 | 36 | 22 | 20 | 13 | 9 | – | – | – | – | – | |
S7 | 40 | 15 | 15 | 10 | 20 | – | – | – | – | – | |
S8 | 27 | 20 | 30 | 12 | 11 | – | – | – | – | – | |
S9 | 34 | 25 | 25 | 7 | 9 | – | – | – | – | – | |
S10 | 38 | 20 | 12 | 12 | 18 | – | – | – | – | – | |
S11 | 40 | 3 | 20 | 7 | 30 | – | – | – | – | – | |
S12 | 44 | 25 | 10 | 5 | 16 | – | – | – | – | – | |
S13 | 45 | – | 8 | 20 | 25 | – | 2 | – | Traces | – | |
S15 | 50 | 13 | 20 | 7 | 5 | – | 5 | – | – | – | |
S16 | 45 | – | 20 | 12 | 22 | – | ~ 1 | – | – | – | |
S17 | 50 | 1 | 15 | 7 | 27 | – | – | – | – | – | |
Siliceous chloritized marble | S18 | 30 | – | – | – | – | – | – | – | 20 | 50 |
Amphibolite | S3 (Core) | Traces | – | 1 | – | – | 84 | – | 13 | 2 | – |
Foliated rock | S19 | Undifferentiated quartz-rich foliated rock | |||||||||
Epidote chlorite schist | S20 | 20 | – | – | – | – | – | – | 45 | 35 | – |
Mesoscopic structures
Microscopic structures
Thin sections | Average angle of mica fish (°) |
---|---|
6 | 23.33 |
7 | 24.73 |
8 | 21 |
9 | 22.13 |
10 | 23.61 |
11 | 23.28 |
12 | 18.22 |
13 | 20 |
15 | 21.18 |
16 | 24.64 |
Overall average | 22.21 |
Geomechanical properties
Strength of the Core samples
Shear strength
Sample | UCS (MPa) | UTS (MPa) | Shear strength (τ; MPa) | Cohesion (c; MPa) | Angle of internal friction (Ф) (°) |
---|---|---|---|---|---|
1–parallel (CGG) | 24.67 | 13.33 | 12.62 | 9.8 | 17 |
1–perpendicular | 14.8 | 12.83 | 7.27 | 6.89 | 4 |
2–parallel (CGG) | 61.69 | 12.83 | 22.15 | 14.07 | 41 |
2–perpendicular | 71.56 | 11.35 | 23.84 | 14.25 | 47 |
4–parallel (CGG) | 71.56 | 16.28 | 27.6 | 17.07 | 39 |
4–perpendicular | 54.29 | 17.76 | 23.36 | 15.5 | 30 |
5–parallel (CGG) | 49.35 | 6.41 | 16.27 | 8.8 | 50 |
5–perpendicular | 41.95 | 7.89 | 14.84 | 9.1 | 43 |
3–parallel (amphibolite) | 91.31 | 11.35 | 30.2 | 16.1 | 51 |
3–perpendicular | 59.23 | 12.33 | 22.55 | 13.51 | 41 |
Results
Discussion
Conclusions
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This study displays some more complicated behavior of multiple deformed rocks under very simple load conditions, which need to be assessed under load and numerical simulation models.
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It is observed that microscopic pervasive crenulation and crenulated cleavage intersection planes and mica fish could potentially induce layer parallel slips that remain perpendicular or parallel to the applied stresses.
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Pervasive slip layers parallel to the applied stresses enhance the strength of tectonically deformed rocks. However, the same planes when perpendicular to the applied stresses decrement the strength of these rocks. The USC is respectively increased or decreased by reactivation of mica fish and S1 crenulated cleavage parallel and perpendicular to the applied load.