Research Article
Influence of Vetiver Root System on Mechanical Performance of Expansive Soil: Experimental Studies
Table 2
Expansive force test results.
| Height | Category | Density (g·cm−3) | Water content (%) | Root content (g·1000 cm−3) | Growth period (d) | Expansive force (kPa) |
| 0∼5 cm | Pure soil | 1.97 | 17.0 | — | — | 73.3 | Root-soil | 1.96 | 17.3 | 1.467 | 90 | 44.5 | 1.92 | 17.2 | 1.283 | 90 | 50.9 | 1.95 | 16.9 | 3.133 | 180 | 30.2 | 1.92 | 16.7 | 3.667 | 180 | 28.2 |
| 5∼10 cm | Pure soil | 1.78 | 17.6 | — | — | 58.2 | Root-soil | 1.76 | 17.8 | 0.983 | 90 | 31.3 | 1.73 | 17.8 | 1.170 | 90 | 28.3 | 1.78 | 17.1 | 2.267 | 180 | 14.1 | 1.74 | 17.6 | 2.083 | 180 | 16.6 |
| 10∼15 cm | Pure soil | 1.66 | 18.6 | — | — | 26.8 | Root-soil | 1.65 | 18.5 | 0.583 | 90 | 12.0 | 1.62 | 18.2 | 0.650 | 90 | 11.9 | 1.63 | 18.2 | 1.706 | 180 | 3.9 | 1.62 | 18.6 | 1.467 | 180 | 5.1 |
| 15∼20 cm | Pure soil | 1.97 | 19.5 | — | — | 62.3 | Root-soil | 1.98 | 19.1 | 0.444 | 90 | 45.2 | 1.96 | 18.8 | 0.517 | 90 | 41.5 | 1.97 | 19.4 | 0.983 | 180 | 21.4 | 1.93 | 18.9 | 0.867 | 180 | 22.6 |
| 20∼25 cm | Pure soil | 1.78 | 19.7 | — | — | 53.6 | Root-soil | 1.74 | 19.5 | 0.383 | 90 | 28.5 | 1.72 | 19.8 | 0.317 | 90 | 30.7 | 1.77 | 19.8 | 0.653 | 180 | 19.0 | 1.74 | 20.1 | 0.517 | 180 | 20.5 |
| 25∼30 cm | Pure soil | 1.65 | 20.8 | — | — | 23.3 | Root-soil | 1.65 | 20.3 | 0.217 | 90 | 12.2 | 1.68 | 20.5 | 0.184 | 90 | 14.6 | 1.67 | 20.7 | 0.451 | 180 | 7.2 | 1.65 | 21.0 | 0.434 | 180 | 5.8 |
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