Leveling Pad Installation for Segmental Retaining Walls

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By Joseph Kowalski
Sep 25, 2008 - 4:11:29 PM

The installation of the leveling pad stone for your retaining wall must begin on stiff soil that is capable of wall support.  A good soil will have an allowable bearing pressure of at least 2000 to 3000 pounds per square foot (a soils engineer can review this).  The soil in the photo to the left is very stiff undisturbed glacial till with a relatively high bearing capacity of at least 4000 psf, which is acceptable for this retaining wall.  You will likely begin by using a trackhoe to excavate down several inches to form a trench that you will fill with the leveling pad gravel.  
After the stiff soil is approved, then the surface of the soil should be cleaned using hand shovels so that there is no loose, soft or disturbed soil present.  A layer of mud on top of good stiff soils will settle and cause the wall to deflect.
  After the leveling pad stone is placed into the trench, then the stone must be compacted in place to increase the density of the stone.  A flat plate vibratory compactor is the best equipment to use when compacting angular granular material such as the DGA stone for a leveling pad at the base of a segmental retaining wall.