For Walls Up To 10 Feet:

  • Recommended Backfill Types = GW, GP, SW, SP, SM, SC
  • Maximum Atterberg Limits (LL and PI) = PI < 20, LL <40
  • Minimum Compaction = 95% of Standard Proctor Density
  • Moisture Content = +/- 2% of optimum moisture
  • Recommended Material Gradation:
SIEVE SIZEPERCENT PASSING
1 in.100
No. 420-100
No. 400-60
No. 2000-35

For Walls 10 Feet to 20 Feet:

  • Recommended Backfill Types = GW, GP, SW, SP, SM, SC
  • Maximum Atterberg Limits (LL and PI) = PI < 6, LL <40
  • Minimum Compaction = 98% of Standard Proctor Density
  • Moisture Content = +/- 2% of optimum moisture
  • Recommended Material Gradation = Same as walls shorter than 10 – feet

For Walls Over 20 Feet:

  • Recommended Backfill Types = GW, GP, SW, SP
  • Maximum Atterberg Limits (LL and PI) = PI < 6
  • Minimum Compaction = 98% of Standard Proctor Density
  • Moisture Content = +/- 2% of optimum moisture
  • Recommended Material Gradation:
SIEVE SIZEPERCENT PASSING
1 in.100
No. 420-100
No. 400-60
No. 2000-15