Thermal Conductivity Of Soil And Rock Classification Manual

837 Words Dec 2nd, 2014 4 Pages
Thermal conductivity of soil is defined as the amount of heat passing in unit time through a unit cross-sectional area of soil under a unit temperature gradient in the direction of heat flow. It is measured in watt per meter per kelvin (W/mk) or also in British thermal unit per foot hour per Fahrenheit (BTU/ft.hr.°F). Knowing thermal conductivity of ground is very important for many geotechnical works. During construction of foundation in permafrost ground, to design underground power line design, for stabilizing ground by freezing, and for utilizing geothermal energy by geothermal heat system we require knowledge of ground thermal conductivity. Thermal properties of ground are difficult to measure exactly. Here estimation of thermal conductivity (k) by different approach is summarized. There are various methods for measuring this parameter including empirical formulas, laboratory tests, and in-situ tests.

Empirical Formula and Soil Classification
Soil and rock classification manual (Salomone et al. 1989) published by international ground source heat pump association categorizes soil/rock into different groups and typical values to each group are given. Also, many empirical formulas based on the soil properties (water content, saturation, porosity) are available for the estimation of k with the accuracy of ±25% in Farouki (1986).

Lab Experiments:
Guarded Hot Plate (GHP) Test:
Guarded hot plate (GHP) test apparatus and test procedure (single and double sided) are…
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