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  • *BYDr.IBRAHIM*Soil Phase Relationships

    BYDr.IBRAHIM**

  • *Soil Phase Relationships* Soil Composition

    Soil Grain or particle 1) Soil Grains 2) & 3) Voids: Water + Air ( )Voids

    Soil Phase Relationships

  • *Soil Phase Relationships* Void Ratio e =high e =Looselow e =Dense

    Soil Phase Relationships**

  • *Soil Phase Relationships* Saturation

    Voids, Vv = Vw + VaAir, VaWater, VwVv = Vw + VaSr =fully saturatedSr = 100 % Dry Sr = 0 %

    Soil Phase Relationships**

  • *Soil Phase Relationships*Mineral soils are composed of:Soil grains Water Air Three Phases of Mineral Soils

    Soil Phase Relationships

  • *Soil Phase Relationships*Weight and volume of soil sample depends on:Specific gravity of soil grains (solids)The size and space between soil grains (voids and pores)Volume of void space filled with water Weight Volume Relationships

    Water

    Solids

    Air

    Soil Phase Relationships

  • *Soil Phase Relationships*PHASE DIAGRAMTo compute the masses (or weights) and volumes of the three different phases. Idealized PrismNotation W = weight V = volume s = soil grainsw = watera = airv = voidst = total

    Soil Phase Relationships**

  • *Soil Phase Relationships*DefinitionsWater content (wc) ( ) is a measure of the water or Moisture present in the soil. Phase DiagramExpressed as percentage.Range = 0 100+%.X 100%

    Soil Phase Relationships

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  • *Soil Phase Relationships*DefinitionsVoid ratio (e) ( ) is a measure of the volume of voids. Phase Diagram

    Soil Phase Relationships

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  • *Soil Phase Relationships*DefinitionsPorosity (n) () is also a measure of the volume of voids, expressed as a percentage. Phase DiagramX 100%Theoretical range: 0 100%

    Soil Phase Relationships

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  • *Soil Phase Relationships*DefinitionsDegree of saturation (Sr) ( ) is the percentage of the void volume filled by water.Phase DiagramRange: 0 100%X 100%DrySaturated

    Soil Phase Relationships

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  • *Soil Phase Relationships*DefinitionsBulk density (gb) ( ) is the density of the soil in the current state. Phase DiagramUnits: t/m3, g/cm3, kN/m3

    Soil Phase Relationships

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  • *Soil Phase Relationships*DefinitionsSaturated density (gsat) ( ) is the density of the soil when the voids are filled with water. : Submerged density (gsub) ( ) is the effective density of the soil when it is submerged. : gsub= gsat - gw

    Soil Phase Relationships**

  • *Soil Phase Relationships*DefinitionsDry density (gd) ( ) is the density of the soil in dry state : Phase DiagramUnits: t/m3, kg/m3, kN/m3

    Soil Phase Relationships

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  • *Soil Phase Relationships*Phase RelationsConsider a unit volume of the soil solids,where Vs = 1. Phase DiagramThe other volumes can be obtained from the previous definitions.Weight = Density x VolumevolumesmassesThe weights can be obtained from:

    Soil Phase Relationships

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  • *Soil Phase Relationships*Phase RelationsConsider a unit volume of the soil solids,where Vs = 1. Phase Diagramvolumesmasses

    Soil Phase Relationships

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  • *Soil Phase Relationships* Phase Relations From the previous definitions,

    soil

    air

    water1GsgwSregwSr eePhase Diagram

    Soil Phase Relationships

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  • *Soil Phase Relationships*Phase Relations

    soil

    air

    water1GsgwSregwSreePhase Diagram

    Soil Phase Relationships

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  • *Soil Phase Relationships* Relative DensityIt is a measure of the soil state of compactness, and expressed as:

    Soil Phase Relationships

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  • *Soil Phase Relationships*EXAMPLE 1A sample of saturated clay has a water content Wc = 47.0% and specific gravity Gs = 2.7. Calculate the voids ratio e, the porosity n, and the saturated unit weight gsat.

    Soil Phase Relationships

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  • *Soil Phase Relationships*EXAMPLE 1Solution Using Prism:

    Soil Phase Relationships

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  • *Soil Phase Relationships*EXAMPLE 2The weight of a wet specimen of clay is 34.62 gm. The dry weight = 20.63 gm. Before drying, the specimen was immersed in mercury and its volume was found to be 24.26 cm3, if Gs = 2.7, calculate the water content Wc, the voids ratio e, and the degree of saturation Sr.Solution:Ww = 34.62 - 20.36 = 14.26 gmWater content, Wc = 70.40%where

    Soil Phase Relationships

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  • *Soil Phase Relationships*

    Vv = V - VsVv = 24.26 - 7.54 = 16.72 cm3Voids ratio, e = 2.22Degree of Saturation, Sr = 85.29%.

    Soil Phase Relationships

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  • *Soil Mechanics*QUESTIONS

    Soil Mechanics

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