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Lab Services: Soil testing

Lab Services: Soil testing

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Test Method Title

Standard Test Method for Determination of Thermal Conductivity of Soil and Soft Rock by Thermal Needle Probe Procedure

Reference Number

ASTM D5334



Test Property

Thermal conductivity

Description of Test

The thermal conductivity is determined by a variation of the line source test method using a needle probe having a large length to diameter ratio to simulate conditions for an infinitely long, infinitely thin heating source. The probe consists of a heating element and a temperature measuring element and is inserted into the specimen. A known current and voltage are applied to the probe and the temperature rise with time is recorded over a period of time. The temperature decay with time after the cessation of heating can also be included in the analysis to minimize effects of temperature drift during measurement. The thermal conductivity is obtained from an analysis of the time series temperature data during the heating cycle and cooling cycle if applicable.

Preferred Test Sample Size

2" x 8"

Number of Test Specimens


Test Specimen Size

2" x 8"


heat flow; temperature; thermal conductivity; thermal probe; thermal properties

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