Annex E


A sample semi-empirical method for bearing resistance estimation

(1) To estimate the design bearing resistance of a foundation on soil, field tests such as the pressuremeter test may be used.

(2) When using the pressuremeter, the design bearing resistance, Rd, of a foundation subjected to a vertical load is related to the limit pressure of the soil by the linear function:

Rd/A' = σv;0 + k p*le


k is the bearing resistance factor

σv;0 is the initial total vertical stress

p*le is the design net equivalent limit pressure (from the pressuremeter test)

and the other symbols defined in 1.6.

(3) Numerical values of the bearing resistance factor k are in the range of 0,8 to 3,0 depending on the type of soil, the embedment depth and the shape of the foundation.

(4) The design net equivalent limit pressure (p*le) is derived from the net limit pressure (p*l), which is defined for a pressuremeter test as the difference (pl – p0) between the limit pressure pl and the at rest horizontal earth pressure p0 at the level of the test; p0 may be determined, from an estimate of the at rest earth pressure coefficient K0 and from the values of the effective overburden pressure q' and the pore-water pressure u, as p0 = K0q' + u.

Eurocode 7 Geotechnical design Part 1 : General rules