the relative proportion of load to be carried by the reinforcement layers
closest to the crest of a wall with uniform reinforcement spacing increases
with increasing horizontal acceleration. This may require a greater
number of layers towards the top of the wall than is required for static
load environments. A similar conclusion was reached by Vrymoed
(1989) using a tributary area approach that assumes that the inertial
force carried by each reinforcement layer increases linearly with height
above the toe of the wall for equally spaced reinforcement layers. Bona-
parte et al. (1986) applied the tributary area method to walls and slopes
but recommended a uniform distribution for the dynamic earth pressure
increment (i.e. Hd 0:5H in Fig. 14.12).