Why are backfill lifts limited in thickness?
Correct Answer
A) Compaction equipment must be able to densify the full lift depth.
Excessive lift thickness can leave loose soil below the compacted surface.
Why This Is the Correct Answer
Excessive lift thickness can leave loose soil below the compacted surface.
Why the Other Options Are Wrong
Option B: Thicker lifts always compact better
In site construction, Thicker lifts always compact better. is the wrong selection for Lift thickness control: it points to Thicker lifts always compact better. but.
Option C: Treat lift thickness limits as only decorative
The trap in C is Lift thickness is only decorative. That selection is wrong because the option delays or omits the controlling step.
Option D: Treat lift thickness limits as only affecting paint warranty
Choice D gives It only affects paint warranty. Its specific error: the action skips the timing, documentation, or field-control step needed for Lift thickness control.
Memory Technique
Picture lift thickness control doing the job; the answer names that job as Compaction equipment must be able to densify the full lift depth.
Reference Hint
Open Pipe and Excavation Contracting, 2011; use by topic index - bedding / backfill / compaction to confirm that Excessive lift thickness can leave loose soil below the compacted surface.
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