Primary Consolidation Settlement (NC Clay)
The slow settlement that governs a foundation on clay, which soil-settlement-elastic names as separate: Sc = (Cc H/(1 + e0)) log10((sigma'0 + d_sigma)/sigma'0). A 10 ft NC clay (Cc 0.25, e0 0.90) under a 1,000 psf footing load settles 2.8 in - several times the immediate elastic dip, over years as water squeezes out. Because it grows with the LOG of the stress ratio, doubling the load increment only lifts it to 4.75 in - the first increment is the costly one. Single NC layer, no time rate. A design aid; the geotechnical engineer of record governs.
Formula and source
Sc_ft = (Cc H / (1 + e0)) log10((sigma'0 + d_sigma) / sigma'0); Sc_in = 12 Sc_ft.
The Terzaghi primary consolidation settlement of a normally-consolidated clay Sc = (Cc H/(1 + e0)) log10((sigma'0 + d_sigma)/sigma'0), with the compression index Cc, as compiled in the Das and NAVFAC references, by name.
Audience
This tile is built for trades and the adjacent professions in the Carpentry and Construction group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.