Constant Head Test Parameters (Coarse Soils)
Water collected in graduated cylinder
Length between manometer ports
Sample area: A = π·D²/4 (D=10cm → 78.5 cm²)
Total head loss across specimen length
Duration of test collection in seconds
Falling Head Test Parameters (Fine Soils)
Cross-sectional area of standpipe tube
Soil sample length
Area of permeameter cylinder
Water head level at time t = 0
Water head level at time t = t
Time interval for head drop
Hazen's Empirical Estimation (Clean Sands)
Empirical factor (typically 0.8 to 1.5, default 1.0)
Grain diameter at 10% passing (from PSD curve)
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