<< Click to Display Table of Contents >> Navigation:  Chapter 9 Geotechnical Data Management > Geotechnical Tests > Entering Test Data > Soil and Aggregates Tests > Consolidation > Calculations

The following calculations are used in this test:

 

 

Initial and Final Water Content

 

w0 = 100 * (MTo - Md) / Md        Initial

 

wf = 100 * (MTf - Md) / Md        Final

 

where,

w0        = Initial water content

wf        = Final water content

MT0        = Initial wet mass

MTf        = Final wet mass

Md        = Dry soil mass

 

 

Initial and Final Dry Density

 

ρ0 = Md / V0                                Initial

 

ρf = ρ0 * H0 / (H0 - DI + DF)                Final

 

where,

ρ0        = Initial dry density

ρf        = Final dry density

V0        = Initial specimen volume

H0        = Initial specimen height

DI        = Initial dial reading

DF        = Final dial reading

 

 

Initial and Final Dry Unit Weight

 

γ0 = ρ0 * γw                                Initial

 

γf =   γ0 * H0 / (H0 - DI + DF)                Final

 

where,

γ0        = Initial dry unit weight

γf        = Final dry unit weight

γw        = Unit weight of water (9.807 kN/m3)

 

 

Initial and Final Void Ratio

 

e0 = SG * V0 / Md - 1                        Initial

 

ef = SG * wf / 100                        Final

 

where,

e0        = Initial void ratio

ef        = Final void ratio

SG        = Specific gravity of specimen

 

 

Initial and Final Saturation

 

S0 = (MT0 - Md) / [A * ρw * (H0 - Hs)] * 100        Initial

 

Sf = (MTf - Md) / [A * ρw (Hf - Hs)] * 100                Final

 

where,

S0        = Initial saturation

Sf        = Final saturation

A        = Cross-sectional area of specimen

Hf        = Final specimen height

Hs        = Equivalent height of solids = Vs / A

Vs        = Volume of solids = Md / (SG * ρw)

ρw        = Density of water (1.0 g/cm3)

 

 

Vertical Strain

 

ε = 100 * (Ri - R + Hc) / H0

 

where,

ε        = Vertical strain

Ri        = Initial dial reading

R        = Final dial reading for set

Hc        = Correction for set

H0        = Initial sample height

 

 

Void Ratio

 

e = e0 - ε * (1 + e0)  / 100

 

where,

e        = Void ratio

 

 

Coefficient of Consolidation

 

Cv = T * HD502 / t

 

where,

Cv        = Coefficient of consolidation

T        = 0.197 for Log of Time method and 0.848 for Square Root of Time method

HD50        = Length of drainage path at 50% consolidation, half the specimen height at the appropriate increment for  double-sided drainage and the full specimen height for one-sided drainage

t        = Time corresponding to the degree of consolidation, T50 for Log of Time method and T90 for Square Root of Time method