The limiting acceleration Ng of this wall is 0.112 g. At this value of
ground acceleration, the dynamic failure plane in the backfill makes a
54.67° angle with the horizontal (8). In modelling the problem, it is assumed
this inclination does not change. This assumption is contrary to
Zarrabi's prediction (19). However, in most dynamic tests on model retaining
walls, such as those performed by Lai (6), a single rupture plane
in the backfill has been observed.
The finite element mesh in Fig. 4(b) is used for modelling this problem.
For this problem, the backfill is descritized up to 6H away from the
wall, where H is the height of the wall. This descretization is adequate,
because frictional nonlinearities in the vicinity of the wall overwhelm all
other effects (8). The slip element at the base of the wall has been assigned
a very large value of normal stiffness, thus restraining the wall
from vertical and rotational movements relative to its base. Thus, the
wall undergoes only translational movements and a direct comparison
can be made with the R-E type models.