ETL 1110-2-352
31 Mar 94
Figure 6. Example calculation of the vertical shear
force for a gravity wall founded on rock
definition sketch in Figure 5 is used to obtain the
value of the correction factor Cθ from Figure 4.
(8) The vertical shear force determined using the
simplified procedure can be incorporated in conven-
checked against the recommended criteria (EM 1110-
Figure 5. Definition sketch and values of the cor-
2-1605, EM 1110-2-2502, EM 1110-2-2602, ETL
rection factor Cs for gravity walls founded on rock
1110-2-22, ETL 1110-2-256, ETL 1110-2-310).
with stepped back sides
When a toe fill of significant height exists, a vertical
shear force at the toe should be included in the equi-
be obtained by including the vertical shear force in
librium calculations if a vertical shear force was
design.
applied to the back side of the wall. Neglecting the
vertical shear force at the toe could result in uncon-
(5) Figure 3 also shows that the limiting value of
servative estimates of the base contact area and the
(Kv)vert develops at lower wall heights for walls with
maximum bearing pressure on the foundation.
loose backfill than for walls with dense backfill.
(9) Use of the simplified procedure to obtain a
(6) Figures 4 and 5 show the values of the cor-
vertical shear force for stability calculations is
restricted to gravity earth retaining walls that satisfy
rection factors Cθ and Cs, respectively, that are to be
the following criteria:
applied.
(a) The vertical displacements within the founda-
(7) An example application of the simplified
tion during construction of the wall and backfilling
procedure is shown in Figure 6. It can be noted that
are negligible when compared with the vertical settle-
the steps in the back side of the wall in Figure 6 are
ment within the backfill due to self-weight. Gravity-
not uniform. An average slope consistent with the
5