Research Article
A Study on the Seepage Flow Characteristics and Disaster-Causing Mechanism of Collapse Column
Table 3
Permeability gradation for rock and earth.
| | Grade of permeability | Standard | Soil type | | Permeability coefficient K (m/s) | Permeability q (Lu) |
| | Mostly impermeable | K < 10−8 | q < 0.1 | Clay | | Slightly permeable | 10−8 ≤ K < 10−7 | 0.1 ≤ q < 1 | Clay-silt | | Weakly permeable | 10−7 ≤ K < 10−6 | 1 ≤ q < 10 | Silt-fine sand | | Moderately permeable | 10−6 ≤ K < 10−4 | 10 ≤ q < 100 | Sand-sand gravel | | Strongly permeable | 10−4 ≤ K < 10−2 | q ≥ 100 | Sand gravel-gravel | | Very strongly permeable | K ≥ 10−2 | | Boulder |
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