BACKFILLING TRENCH EXCAVATIONS

IN THE SUMMER OF 1969, SEVENTEEN DUMMY TRENCHES WERE EXCAVATED AND BACKFILLED USING THE ORIGINAL A-6 CLAY LOAM SOIL. THE BACKFILL WAS COMPACTED TO DENSITIES FROM 95.2 TO 103.5 PERCENT OF AASHO T-99 MAXIMUM DENSITY. SURFACE SETTLEMENTS AND SETTLEMENTS AT DEPTHS OF 0.7, 2.0, 4.0 AND 6.0 FT WERE MEASURED OVER A PERIOD OF 21 MONTHS. THE SETTLEMENTS WERE MOSTLY IN THE 0.04- TO 0.08-FT RANGE. ONLY FOUR SETTLED LESS THAN 1/2 IN. SEVENTY PERCENT OF THE SETTLEMENT OCCURRED DURING THE FIRST FALL AND SPRING AFTER CONSTRUCTION. OBSERVED SETTLEMENT WAS DOMINANTLY IN THE UPPER 2 FT OF THE 6-FT BACKFILL. THERE WAS ESSENTIALLY NO MOVEMENT AT THE BOTTOM OF THE TRENCH. IT IS CONCLUDED THAT SETTLEMENTS OF APPROXIMATELY 1/2 TO 1 IN. MUST BE ANTICIPATED FOR TRENCHES WITH PLASTIC SOILS EVEN WHEN COMPACTED IN RELATIVELY THIN LAYERS TO RELATIVELY HIGH DENSITIES. /AUTHOR/

• Supplemental Notes:
  • No 610, 56 PP, 23 FIG, 9 TAB
• Corporate Authors:

  University of Minnesota, Minneapolis

  Department of Civil and Mineral Engineering, 122 Civil and Mineral Engineering Building
  Minneapolis, MN  United States  55455-0220
• Authors:
  • Kersten, M S
  • Skok, E L
• Publication Date: 1971-6-30

Subject/Index Terms

• TRT Terms: Backfilling; Compaction; Excavations; Plastic soils; Settlement (Structures); Soil compaction test; Soils; Trench backfill
• Old TRIS Terms: Compaction tests; Settlement rate
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00233251
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 10 1972 12:00AM