Civil and Building Engineering.

The differences in settlement for a general shear failure and a local shear failure are shown in Figure 7.4, where the general shear failure is depicted by the solid line. The footing on loose soil is expected to settle a large amount compared to the footing on dense soil, which Terzaghi elected to reflect by reducing the values of the bearing capacity factors for loose soil. A proposed reduction in bearing capacity to deal with excessive settlement is disregarded here because Chapter 9 deals with short-term settlement of shallow foundations. The engineer may reduce the load on the foundation if the immediate settlement is deemed excessive.

Figure 7.2 Model used by Terzaghi in developing valves for bearing-capacity factors (from Terzaghi, 1943, p. 121).

Figure 7.3 Terzaghi’s bearing-capacity factors (from Terzaghi, 1943, p. 125).