Geology Reference
In-Depth Information
Table 5.1.
Some typical values of thermal conductivity, thermal diffusivity, and volumetric heat
capacity for various materials.
(A) Thermal conductivity of various materials
Material
Thermal Conductivity
Material
Thermal Conductivity
(k) (W/m K)
(k) (W/m K)
Air
0.024
Rocks
Water
0.605
Shale
1.5
Ice (at 0 °C)
2.23
Granite
1.7-4.0
Snow
Building materials
Loose, new
0.086
Concrete
1.3-1.7
On ground
0.121
Steel
35-52
Dense
0.340
Wood
0.12-0.16
Organic material
Asbestos
0.07
Peat, dry
0.05
Polystyrene
0.033
Peat, saturated unfrozen
0.50
Peat, saturated frozen
2.00
(B) Heat capacities of various materials
Material
Heat Capacity, c
Volumetric Heat Capacity, C
Btu/ft.
3
°F
MJ/m
3
-K
Btu/lb.°F
kJ/kg-K
Air
0.24
1.000
0.0187
0.00125
Water
1.00
4.187
62.4
4.187
Ice
0.50
2.094
28.1
1.88
Soil minerals
0.17
0.710
28.0
1.875
Organic soil
0.40
1.674
37.5
2.52
Polystyrene insulation
0.24
1.000
0.65
0.0435
Concrete
0.21
0.895
30.0
2.01
Asphalt
0.4
1.674
37.5
2.52
(C) Thermal diffusivities of various materials
Material
Thermal Diffusivity,
α
ft.
2
/hr. × 10
−3
m
2
/s
10
−7
×
Water
5.61
1.45
Fresh snow
12.8
3.3
Ice
46.2
11.9
Granite
58
15
Limestone
27
7
Dolomite
78
20
Sandstone
39
10
Shale
31
8
Quartzite
174
45
Sources: Johnston (1981); Williams and Smith (1989).
If there is a change in the climatic conditions at the ground surface, the thickness of
the permafrost will change accordingly. For example, an increase in mean surface tem-
perature will result in a decrease in permafrost thickness, while a decrease in surface
temperature will give the reverse. For example, Equation (5.2) can be used to calculate
