Consolidation Time Rate (Terzaghi)
Terzaghi 1-D consolidation: Tv = (pi/4)(U/100)^2 for U <= 60% else 1.781 - 0.933 log10(100-U), time t = Tv Hdr^2/cv. U 90%, cv 0.1 ft^2/day, Hdr 10 ft -> Tv 0.848, 848 days; U 50% -> 196 days (the decelerating curve). Hdr is half the layer for double drainage (a 4x time swing). The engineer of record governs.
Formula and source
Tv = (pi/4)(U/100)^2 for U <= 60%, else 1.781 - 0.933 log10(100 - U); t = Tv Hdr^2 / cv.
Terzaghi one-dimensional consolidation theory (time factor Tv), as compiled in Das, Principles of Geotechnical Engineering, by name.
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