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The following calculations are used in this test:
Deformation
The axial deformations can be specified directly or using deformation dial readings. When using dial readings they are converted to actual deformations using a dial constant.
Da = (Ra - Rai) * ADC
where,
Da = Axial deformation
Ra = Axial dial reading
Rai = Initial axial dial reading
ADC = Axial dial constant
Axial Load
The Axial loads can be specified directly or using readings from a load ring. When using readings from a load ring the readings are converted to loads either using load ring constants or a linear equation.
Load Ring Constant
If R < Crossover Pa = R * LRC1
If R > Crossover Pa = Crossover * LRC1 + (R - Crossover) * LRC2
Linear
Pa = M * R + C
where,
Pa = Axial load
R = Load dial reading
LRC1 = Load ring constant 1
LRC2 = Load ring constant 2
M = Linear multiplier
C = Linear constant
Axial Strain
εa = Da / h
where,
εa = Axial strain
Da = Axial deformation
h = Initial height of specimen
Axial Stress
σ = Pa / A
where,
σ = Axial stress
Pa = Axial load
A = Cross-sectional area = A0 / (1 - εa)
A0 = Initial cross-sectional area = π * d2 / 4
d = Initial diameter
Water Content
wi (%) = 100 * (Mbwt - Mbdt) / (Mbdt - Mbt)
where,
wi = Initial percentage water content
Mwt = Mass of tare and wet specimen
Mdt = Mass of tare and dry specimen
Mt = Mass of tare
Dry Density
ρi = Mw / V / (1+ wi/100)
where,
ρi = Initial dry density
Mw = Wet sample mass
V = Sample volume
wi = Initial water content (%)
Dry Unit Weight
γi = ρi * γw
where,
γi = Initial dry unit weight
γw = Unit weight of water (9.807 kN/m3)
Saturation
Si (%) = 100 * Vwi / Vvi
where,
Si = Initial saturation
Vwi = Initial volume of water in sample = (Mw - Ms) / ρw
Vvi = Initial volume of voids = Vi - Vs
Vs = Volume of solids = Ms / (SG * ρw)
Ms = Mass of solids = Mw / (1 + wi / 100)
ρw = Density of water (1.0 g/cm3)
SG = Specific gravity
Void Ratio
ei = Vvi / Vs
where,
ei = Initial void ratio