THERMAL PROPERTIES OF SOILS

CALCULATION OF DEPTH AND RATE OF FROST PENETRATION OR DEPTH AND RATE OF THAW OF FROZEN SOILS REQUIRES A KNOWLEDGE OF THE THERMAL PROPERTIES OF SOILS. THESE PROPERTIES INCLUDE THERMAL CONDUCTIVITY, SPECIFIC HEAT AND VOLUMETRIC HEAT CAPACITY, AND THERMAL DIFFUSIVITY. DEFINITIONS ARE PRESENTED OF THESE TERMS, WITH THE UNITS USED IN THE PAPER. THE IMPORTANT ASPECT OF TEMPERATURE ON THE THERMAL CONDUCTIVITY OF SOIL IS WHETHER THE SOIL IS FROZEN OR NOT. THE DIFFERENCE IN CONDUCTIVITY OF FROZEN AND UNFROZEN SOILS IS CHIEFLY DEPENDENT ON MOISTURE CONTENT. TESTS HAVE SHOWN THAT AN INCREASE IN THE DRY DENSITY OF A SOIL, THE PERCENTAGE OF MOISTURE REMAINING THE SAME, RESULTS IN AN INCREASE IN THERMAL CONDUCTIVITY. IF SOILS OF DIFFERENT TEXTURE ARE TESTED AT EQUAL MOISTURE CONTENTS AND DENSITIES IT WILL BE FOUND THAT THE COARSE-GRAINED MATERIALS, SUCH AS GRAVELS AND SANDS,WILL HAVE HIGH CONDUCTIVITY; FINE-GRAINED SOILS SUCH AS SILT LOAMS AND CLAYS, LOW CONDUCTIVITY; AND INTERMEDIATE-TEXTURED SOILS VALUES BETWEEN THESE TWO. DIFFUSIVITY VALUES ARE OF INTEREST IN FROST CALCULATIONS SINCE THEY INDICATE THE RATE AT WHICH A SOIL WILL CHANGE TEMPERATURE WHEN THE TEMPERATURE OF THE SURROUNDING MEDIUM CHANGES. IN CALCULATIONS INVOLVING THE FREEZING OR THAWING OF A SOIL IT IS NECESSARY TO TAKE INTO ACCOUNT THE LATENT HEAT OF FUSION OF THE ICE. NUMERICAL VALUES OF THE VARIOUS CONSTANTS PERMIT MATHEMATICAL CHECKS OF VARIOUS HEAT-TRANSFER PROBLEMS IN CONNECTION WITH FROST ACTION IN SOILS. THE NUMERICAL VALUES OF SPECIFIC HEAT AND THERMAL CONDUCTIVITY PRESENTED WITH WHICH DIFFUSIVITIES MAY ALSO BE CALCULATED, ARE OFFERED FOR USE IN SUCH CALCULATIONS.

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  • Supplemental Notes:
    • pp 161-166, 3 FIG, 17 REF Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
  • Authors:
    • Kersten, M S
  • Conference:
  • Publication Date: 1952

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  • Accession Number: 00237849
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 26 1970 12:00AM