ABSTRACT
FR = ca B+Rtan8+Pp (19.5) R = total vertical force =Ws + We + Pv ' 8 = angle of wall friction ca = unit adhesion If the bottom of the base slab is rough, as in the case of concrete poured directly on soil, the
coefficient of friction is equal to tan ljJ, ljJ being the angle of internal friction of the soil. The factor of safety against sliding is
In case F s < 1.5, additional factor of safety can be provided by constructing one or two keys
at the base level shown in Fig. 19.6b. The passive pressure Pp (Fig. 19.6a) in front of the wall should not be relied upon unless it is certain that the soil will always remain firm and undisturbed.
