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Can a defective core trench be helped by pasting and compacting more clay to the inside and bottom of pond ? FYI - pond builder only used a bulldozer for compaction work- which (despite my pleas) appears to have been a big mistake. So trying to decide whether to compact what is already there (despite losing advantage of doing it in 6" lifts) and then adding more to the bottom and side and compacting that in 6" lifts -- or spending the $$ redoing the core trench. [/quote]

Has anyone tried dynamic compaction? Seems like it would work, but might be fairly expensive. A crane drops a flat weight, moves, drops it again. Google the words "dynamic compaction".