Failure of an 8-Meter-High Segmental Block Wall in the Northeast United States - Reinforced Soil Engineering: Advances in Research and Practice - page 113

Figure 3 Second failure.

the joints were observed to be open, and the bell of the second pipe section from
the inlet was broken, and partially missing. Also, the inlet and pipe were bedded
in open graded stone, which may have connected directly with the drainage
material behind the wall.
The parties involved generally agreed that the failure was most likely due
to hydrostatic pressure buildup from the leaking storm sewer. This was due to the
reports of significant amounts of water being introduced into the storm drain
system, the location of the failure at the storm drain inlet, and the open joints and
crushed stone bedding of the storm drain pipe. The low density of the backfill was
noted as an additional factor contributing to the failure. A subsurface exploration