⎧7.7q3.0(1-q) q < 0.20 coarse
κ s = ⎨ q (1-q)
.
(4.27)
7.7 2.0
all others
⎩
and κ w = 0.0018Tj,i + 0.0787 , κi = 488.19Tj-i1 + 0.4685 . Farouki (1981) found that
,
Johansen's method for predicting soil thermal conductivity matched the existing data
well except for the case of dry (Sr < 0.2), unfrozen, coarse soils. Since the recommended
methods for this situation rely on unavailable curve fitting parameters, Johansen (1975) is
used for all conditions. The physical properties used in Equations (4.23)(4.27) for the 15
USCS soil types are given in Table 4.3.1.
The soil thermal diffusivity, kth, is equal to
κ
kth =
(4.28)
C
where the volumetric heat capacity, C, is defined as (Farouki 1981)
C = (1 - n ) γ d Cs + ( ww) ρwCw + ( n - [ ww + wi ]) ρaCa + ( wi ) ρi ( -13.3 + 7.8Tj,i ) (4.29)
and Cw = 4217.7 J/kgK is the specific heat of water, Ca = 1250.0 J/kgK is the specific
heat of air, and Cs is the specific heat of solids given in Table 4.3.1.
Table 4.3.1 Default Soil Properties
Organic
Bulk
Specific
Quartz
Fraction
Heat3
1
1
Content2
Dry Density Porosity
Albedo
θof
Cs (J/kg⋅K)
ε
α
Soil Type γd (g/cm3)
Fine/Coarse*
n
q
5
0.2965
GW
1.95
0.92
0.40
0.65
0.00
820.0
1
2.165
0.2035
GP
0.92
0.40
0.65
0.00
820.0
1
1.915
0.3245
GM
0.95
0.40
0.65
0.00
820.0
1
1.875
0.344
GC
0.92
0.40
0.65
0.00
820.0
1
1.8765
0.3205
SW
0.92
0.40
0.80
0.00
830.0
1
1.5945
0.4155
816.47
SP
0.92
0.35
0.80
0.00
1
1.4745
0.5265
SM
0.92
0.35
0.80
0.05
850.6
1
1.885
0.4005
SC
0.92
0.35
0.80
0.05
830.0
1
1.4575
0.4645
845.77
ML
0.94
0.40
0.35
0.10
2
1.5895
0.4225
854.17
CL
0.97
0.23
0.05
0.10
2
1.1655
0.5335
837.47
OL
0.955
0.265
0.20
0.25
2
1.5175
0.4575
845.77
CH
0.98
0.30
0.05
0.10
2
1.0601
0.5471
MH
0.94
0.30
0.35
0.10
830.0
2
0.8411
0.8924
866.77
OH
0.955
0.265
0.20
0.25
2
PT
0.25
0.70
0.92
0.40
0.05
0.50
830.0
2
SMSC
1.601
0.3961
(MC)
0.92
0.40
0.80
0.05
830.0
1
CLML
1.6175
0.3975
(CM)
0.96
0.30
0.20
0.10
830.0
2
1.8765
0.3205
EV
0.92
0.40
0.80
0.00
830.0
1
0.906
0.406
CO
2.185
0.020
0.00
850.0
0.946
0.1256
AS
2.500
0.020
0.00
880.0
RO
2.700
0.020
0.89
0.40
0.00
800.0
SN
0.920
0.020
0.90
0.70
0.00
1
Sullivan et al. (1997), p. 28, 38, and 51
2
Tarnawski et al. (1997), p. 96
36
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