SOIL COMPOSITION -Ms Ikmalzatul

Soil: A 3-Phase Material Air Water Solid

The Mineral Skeleton Solid Particles Volume Voids (air or water)

Three Phase Diagram Air Water Solid Idealization: Mineral Skeleton

Fully Saturated Soils Water Solid Mineral Skeleton Fully Saturated

Dry Soils Air Solid Dry Soil Mineral Skeleton

Partly Saturated Soils Solid Air Water Mineral Skeleton Partly Saturated Soils

Three Phase System Air Water Solid Volume Weight Va Wa~0 Vv Vw Ww WT VT Vs Ws Volume Weight

Weight Relationships Weight Components: Weight of Solids = Ws Weight of Water = Ww Weight of Air ~ 0

Volumetric Relationships Volume Components: Volume of Solids = Vs Volume of Water = Vw Volume of Air = Va Volume of Voids = Va + Vw = Vv

Volumetric Relationships Volume Components: Volume of Solids = Vs Volume of Water = Vw Volume of Air = Va Volume of Voids = Va + Vw = Vv

Specific Gravity Unit weight of Water, w w = 1.0 g/cm3 (strictly accurate at 4° C) w = 62.4 pcf w = 9.81 kN/m3

Specific Gravity Iron 7.86 Aluminum 2.55-2.80 Lead 11.34 Mercury 13.55 Granite 2.69 Marble 2.69 Quartz 2.60 Feldspar 2.54-2.62

Specific Gravity, Gs

Example: Volumetric Ratios Determine void ratio, porosity and degree of saturation of a soil core sample Data: Weight of soil sample = 1013g Vol. of soil sample = 585.0cm3 Specific Gravity, Gs = 2.65 Dry weight of soil = 904.0g

Example Air Water Solid Wa~0 134.9cm3 W =1.00 243.9cm3 109.0g Volumes Weights

Example Air Water Solid 134.9cm3 W =1.00 243.9cm3 109.0cm3 585.0cm3 Volumes s =2.65 341.1cm3 109.0cm3 243.9cm3 134.9cm3 W =1.00

Soil Unit weight (kN/m3) Bulk (or Total) Unit weight  = WT / VT Dry unit weight d = Ws / VT Buoyant (submerged) unit weight b = - w

Typical Unit weights

THE END