For yielding walls, lateral earth pressures can be computed assuming active conditions
and wedge theory, using a planar surface of sliding defined by the Rankine theory.
Table 8.1 provides soil properties for computing active earth pressures for five types
of soil. Table 8.2 provides friction factors and adhesion for dissimilar materials. See
Figs. 8.10 and 8.11 for the magnitude and location of resultant forces on retaining
walls considering various types of soil backfill and backslide geometries. The pressures
presented in these figures assume mobilization of the soil shear strength along the
entire Rankine active failure plane, extending uninterrupted from the ground surface at
the base of the wall or to the location on the wall at which the total earth load is being
computed. Figure 8.11 shows the failure surface geometry and associated earth pressure
distributions for various design conditions. If the soil behind the wall consists of more
than one soil type, the design earth pressure should be determined using the weighted
average of the properties of the soil types within and along the theoretical failure plane