4.5 MEYERHOF'S BEARING CAPACITY THEORY

In 1951, Meyerhof published a bearing capacity theory which can be applied to rough shallow and deep foundations. The failure surface at ultimate load under a continuous foundation as assumed by Meyerhof (1951) is shown in Fig. 4.14a and b. In this figure, abc is the elastic triangular wedge shown in Fig. 4.13, bcd is the radial shear zone with cd being an arc of a log spiral, and bdef is a mixed shear zone in which the shear varies between the limits of radial and plane shear depending on the depth and roughness of the foundation. The plane be is referred to as an equivalent free surface. The normal and shear stresses on the plane be are p _o and s _o, respectively. The superposition method is used to determine the contribution of cohesion ( c), p _o, and ? and ? on the ultimate bearing capacity ( q _u) of the continuous foundation and can be expressed as

Figure 4.14: Slip line fields for rough strip foundations.

where

Derivations for N _c and N _q ( ??0, ?=0, p _o ?0 c ?0):

For this case, the center of the log spiral [Eq. (4.1)] arc cd is taken at b. Also, it...