THE EFFECTIVENESS OF SUBSOIL DRAINAGE OF PAVED AREAS ON TWO HEAVY CLAY SITES

SUB-SOIL DRAINAGE IS OFTEN INSTALLED TO PREVENT THE WATER-TABLE BENEATH THE ROAD STRUCTURE FROM RISING TO FORMATION LEVEL. EXPERIMENTS ARE DESCRIBED WHICH DETERMINE THE EFFECTIVENESS OF SUB-SOIL DRAINS LAID ROUND PAVED AREAS 9 M (30 FT) SQUARE AND 15 CM (6 IN) THICK ON TWO HEAVY CLAY SITES. AT THE FIRST SITE, ON A CLAY OF PERMEABILITY ABOUT 10 TO THE MINUS 4 POWER TO 10 TO THE MINUS 5 CM/S ( 10 TO 100 FT/YR), SUB-SOIL DRAINS 0.6 AND 1.2 M (2 AND 4 FT DEEP LOWERED THE WATER-TABLE TO 0.4 AND 0.6 M (1 1/4 AND 2 FT) BELOW THE SURFACE RESPECTIVELY, PROVIDED THAT ANY CRACKS IN THE PAVED AREA WERE PROMPTLY SEALED TO KEEP OUT SURFACE WATER. AT THE SECOND SITE, ON A CLAY OF PERMEABILITY ABOUT 10 TO THE MINUS 8 CM/S, SUB-SOIL DRAINAGE ALSO LOWERED THE WATER-TABLE, BUT ONLY AFTER THE PAVED AREA HAD BEEN COVERED WITH IMPERMEABLE POLYTHENE SHEET FOR AT LEAST THREE MONTHS. THE EFFECT OF LOWERING THE WATER-TABLE ON THE STABILITY OF THE FORMATION IS CONSIDERED, AND IT IS CONCLUDED THAT SUB-SOIL DRAINAGE IS LIKELY TO GIVE LITTLE SAVING IN COST OF FLEXIBLE PAVEMENT CONSTRUCTION ON HEAVY CLAYS. SUB-SOIL DRAINAGE MAY BE OF MORE VALUE ON SILTY SOILS, FOR LIGHTLY CONSTRUCTED ROADS, OR AS A CONSTRUCTION EEXPEDIENT. /RRL/AUTHOR/

  • Supplemental Notes:
    • No 186, pp 45, 20 FIG, 3 TAB, 3 PHOT, 15 REF
  • Corporate Authors:

    MINISTRY OF TRANSPORT, LONDON (UK)

    ,    
  • Authors:
    • FARRAR, D M
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00232097
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Apr 9 1971 12:00AM