Bearing capacity on drained subsoil

One of the following approaches is available to assess the bearing capacity of a foundation if drained conditions are assumed:
- standard analysis

- according to CSN 731001 "Základová pùda pod plošnými základy" approved 8.6. 1987

- according to Polish standard PN-81 B - 03020 "Grunty budowiane, Posudowienie bezpošrednie budowli, Obliczenia statyczne i projekktowanie" from year 1982

- according to Indian standard IS:6403-1981 "Code of Practice for Determination of Bearing Capacity of Shallow Foundations" from year 1981

- according to EC 7-1 (EN 1997-1:2003) "Design of geotechnical structures – Part 1: General rules"

- according to NCMA Segmental retaining walls manual, second edition.

All approaches incorporate coefficients due to Brinch – Hansen (see standard analysis) to account for inclined ground surface and inclined footing bottom.

Assuming drained conditions during construction the soil below spread footing deforms including both shear and volumetric deformations. In such a case the strength of soil is assumed in terms of effective values of the angle of internal friction φ_ef and the effective cohesion c_ef. It is also assumed that there is an effective stress in the soil equal to the total stress (consolidated state). Effective parameters φ_ef , c_ef represent the peak strength parameters.

Owing to the fact that the choice of drained conditions depends on a number of factors (rate of loading, soil permeability, degree of saturations and degree of overconsolidation) it is the designer's responsibility to decide, depending on the actual problem being solved, if the effective parameters should be used.