m²/d
square meter per day
Diffusivityexact by definition
The square metre per day is exactly 1/86400 m²/s. It is the standard unit of the coefficient of consolidation in geotechnical practice: typical clays fall between about 0.1 and 10 m²/day, and settlement-time calculations using Terzaghi's theory are worked in these units throughout.
Watch out: Consolidation coefficients are reported in a mess of units across the literature, including cm²/s, m²/year and ft²/day, and they span several orders of magnitude between soils. Always check the unit on a tabulated value before putting it into a time factor, since the answer is a settlement duration and the error compounds directly.
| 1 m²/d | 11.574074 mm²/s |
Solvers that use diffusivity