Table 2 Conventional and traditional soil features.
Conventional soil features | |
|---|---|
Specific gravity | The ratio of the density of the soil particles to the density of water, used to make conclusions regarding mineral content and type of soil. |
Optimum moisture content | Percentage moisture at which the soil compacts most, needed for determining slope stability under load. |
Sand (%) | Indicates the percentage of coarse-grained fragments; higher sand content improves drainage and reduces cohesion. |
Plasticity index (PI) (%) | Range of moisture within which soil acts plastically; higher values reflect greater capacity for deformation under stress. |
Plastic limit (PL) (%) | Critical moisture percentage at which soil begins to act plastically, crucial to workability and slope performance. |
Fines content (%) | Silt and clay particle percentage; affects permeability and cohesion, influencing slope strength. |
Liquid limit (LL) (%) | Percentage at which moisture content transforms soil into liquid state from plastic; useful for classifying soil behavior under conditions of saturation. |
Saturated water content (%) | Moisture content at the condition when pores in soil are saturated with water, influencing drainage capacity as well as saturated weight. |
Porosity | Porosity measures the volume of voids in the soil; higher porosity provides greater retention of water and affects the rate of infiltration. |
Gravel (%) | Percentage of coarse particles, which tend to improve drainage and reduce compaction of the soil. |
Particle size | Particle Size Range of particle sizes in the sample; determines texture, permeability, and cohesion. |
Saturated unit weight | Saturated Unit Weight Weight of the saturated soil per unit volume; critical to determine stability for full saturation. |
Traditional soil features | |
|---|---|
Color of the soil 1. Red 2. Brown 3. Black 4. White 5. Green 6. yellow | Applied to predict fertility and drainage: red/brown = good drainage; black = high in organic matter; yellow = poor drainage; white or green soils indicate mineral or salt. |
Content 1. Sand 2. Slit 3. Gravel 4. Clay 5. Rocks and Debris 6. Coarseness | Utilized to sort soil textures and types by appearance and texture, affecting drainage, cohesion, and root penetration. |
Related to water 1. Retention 2. Drainage 3. Moisture 4. Dryness 5. Hardness 6. Smoothness 7. Density | Symbolizes soil-water relations impacting saturation potential and mechanical response to rainfall. |
Smell 1. Earthy 2. Musty 3. Faul | Smell points to aeration and biological activity: earthy connotes healthy conditions, musty or stinking can suggest poor drainage or anaerobic areas. |
Taste 1. Sweetness 2. Saltness | Historically associated with pH and mineral status, which may be related to vegetation cover and soil chemistry. |
Fertility 1. Fertile 2. Plant health 3. Deforestation 4. Vegetation cover | Refers to the biological productivity and ecological stability of the soil, both being associated with erosion and slope stability. |
Field test 1. Stickness 2. Crumbling 3. Clump | Textural features like stickiness (clay content), crumbling (structure), and clumping (root permeability) provide quick information regarding soil stability. |
