Evaluation of the results
2022-10-18
Combining the results and compare with the literature
- The results of two cyclic direct shear tests are presented.
- Tested material is known as Huston sand (HN30).
- Confining pressure may have influence over dynamic properties of the soil. These two tests differ by the vertical stress (120 & 80 kPa); consequently, the confining pressure of them differs.
- The tests approve each other as graphs show. As other investigations show, confining pressure has neglect able influence at small strain and reverse relation in intermediate strain 1 ; This can be concluded from the results, to some how.
- Calculated values are located on the appropriate graphs, borrowed from the thesis by Stefania Gobbi (2020).
It seems that although stiffness values are in the range but damping is overestimated in most cases. Using different approaches (direct shear versus triaxial) or different drainage conditions may be among the sources of differences.
- The graphs by Stefania cover part of the strain ranges in which is tested in the GEOLAB.
- Estimated values of stiffness and damping are as follow:
| File ID | Group | Applied Disp. (mm) | Strain (%)-LVDT | Damping(%) | Stiffness(MPa) |
|---|---|---|---|---|---|
| Hn_80_160 | 1 | 0.001 | 0.001 | -0.25 | 7.473 |
| Hn_80_160 | 2 | 0.002 | 0.002 | 5.68 | 44.452 |
| Hn_80_160 | 3 | 0.005 | 0.004 | 11.34 | 58.665 |
| Hn_80_160 | 4 | 0.010 | 0.013 | 10.72 | 43.261 |
| Hn_80_160 | 5 | 0.020 | 0.036 | 11.70 | 35.278 |
| Hn_80_160 | 6 | 0.050 | 0.118 | 20.24 | 23.339 |
| Hn_80_160 | 7 | 0.100 | 0.232 | 23.78 | 17.618 |
| Hn_80_160 | 8 | 0.200 | 0.380 | 24.71 | 13.798 |
| Hn_80_160 | 9 | 0.500 | 1.215 | 32.43 | 5.344 |
| Hn_80_160 | 10 | 1.000 | 3.193 | 34.57 | 2.492 |
| Hn_80_160 | 11 | 1.999 | 7.310 | 36.27 | 1.209 |
| Hn_80_160 | 12 | 4.998 | 19.737 | 47.22 | 0.443 |
| Hn_80_160 | 13 | 0.020 | 0.038 | 13.98 | 34.914 |
| Hn_80_160 | 14 | 0.010 | 0.015 | 6.11 | 44.144 |
| Hn_80_80 | 1 | 0.001 | 0.001 | 5.26 | 10.278 |
| Hn_80_80 | 2 | 0.002 | 0.002 | 10.50 | 50.348 |
| Hn_80_80 | 3 | 0.005 | 0.005 | 11.97 | 44.358 |
| Hn_80_80 | 4 | 0.010 | 0.016 | 10.27 | 34.675 |
| Hn_80_80 | 5 | 0.020 | 0.040 | 12.01 | 28.691 |
| Hn_80_80 | 6 | 0.050 | 0.091 | 18.14 | 21.787 |
| Hn_80_80 | 7 | 0.100 | 0.161 | 20.33 | 16.964 |
| Hn_80_80 | 8 | 0.200 | 0.301 | 23.87 | 11.267 |
| Hn_80_80 | 9 | 0.500 | 1.294 | 33.44 | 2.923 |
| Hn_80_80 | 10 | 1.000 | 3.333 | 36.23 | 1.316 |
| Hn_80_80 | 11 | 1.999 | 7.507 | 37.77 | 0.639 |
| Hn_80_80 | 12 | 4.998 | 19.963 | 57.59 | 0.206 |
| Hn_80_80 | 13 | 2.999 | 11.648 | 41.32 | 0.390 |
Clean Hostun sand, Dr=30, P´=50, 100, 200 kPa
Stefania Gobbi, 2020↩︎