BACKFILLING TRENCH EXCAVATION

INVESTIGATION WAS MADE TO DETERMINE THE PROCEDURES REQUIRED BY VARIOUS WIDELY USED COMPACTING EQUIPMENT TO ENSURE RELATIVELY SETTLEMENT FREE BACKFILL OF SLIT TYPE TRENCHES. TEST TRENCHES WERE EXCAVATED, BACKFILLED AND COMPACTED USING VARIOUS COMPACTORS AND PROCEDURES IN THE TRAVELED PORTION OF FOUR DIFFERENT ROADWAYS. THE LOCATIONS OF THE SITES FOR THE TEST TRENCHES WERE SELECTED SO THAT TWO SITES WERE IN PLASTIC SOILS AND TWO IN GRANULAR SOILS. A TOTAL OF 67 TRENCHES WERE EXCAVATED AND BACKFILLED UNDER CONTROLLED CONDITIONS. THEY WERE COMPACTED USING FIVE DIFFERENT COMPACTORS (HYDRA-HAMMER, BUTTON HEAD, PLATE TAMPER, PLATE VIBRATOR AND VIBRATORY ROLLER) AND 28 DIFFERENT PROCEDURES. ALL PROCEDURES WHICH APPEARED TO HAVE SOME PROMISE WERE DUPLICATED ON TWO TRENCHES AT THE SAME SITE. IN SEVERAL CASES THESE PROCEDURES WERE REPEATED AGAIN AT THE OTHER SITE OF THE SAME SOIL TYPE. DENSITY AND MOISTURE DETERMINATIONS WERE MADE PRIOR TO EXCAVATION AND AGAIN AFTER BACKFILLING AND COMPACTION. SETTLEMENT IN THE 67 TRENCHES VARIED FROM 3/8 IN. TO 8 1/2 IN. ONLY SIX OF THE TRENCHES (ALL AT SITES HAVING GRANULAR SOILS) SETTLED 1/2 IN. OR LESS. NONE OF THE 28 COMPACTION PROCEDURES RESULTED IN AN AVERAGE SETTLEMENT OF 1/2 IN. OR LESS. NO SIGNIFICANT CORRELATIONS WERE FOUND BETWEEN SETTLEMENT AND EITHER AVERAGE DENSITY OR AVERAGE MOISTURE CONTENT OF THE COMPACTED BACKFILL. IN GENERAL, SETTLEMENT DECREASED WITH AN INCREASE IN NUMBER OF COMPUTER PASSES AND/OR A DECREASE IN LIFT HEIGHT. IN GENERAL, MOST OF THE SETTLEMENT OCCURRED DURING THE FIRST SIX WEEKS AFTER CONSTRUCTION AND/OR AFTER THE FIRST SPRING THAW WHICH THE TRENCHES EXPERIENCED. TRENCHES WHICH HAD LESS THAN 2 IN. TOTAL SETTLEMENT GENERALLY DID NOT SETTLE IN BETWEEN THESE PERIODS. /AUTHOR/

  • Supplemental Notes:
    • Hpr, 610
  • Corporate Authors:

    Minnesota Department of Highways

    ,    

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  United States  20590
  • Authors:
    • Kruse, C G
    • Yoerg, W N
  • Publication Date: 1968

Subject/Index Terms

Filing Info

  • Accession Number: 00214478
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS, STATEDOT
  • Created Date: Mar 10 1994 12:00AM