Failure of an 8-Meter-High Segmental Block Wall in the Northeast United States - Reinforced Soil Engineering: Advances in Research and Practice - page 112

Figure 2 First failure.

slightly more than 50% passing the No. 200 Standard Sieve and moderate to low
plasticity. This material did not meet the material classification specified on the
design documents.
A modified proctor test (ASTM D1557) was performed on one bulk sample
obtained from the failure area. The result of this test indicates that the maximum
dry density for this material was about 19.3 kN/m 3 at optimum moisture of about
10.8%. In-place density testing of the soil within the failed reinforced soil zone
generally ranged from about 14.0 kN/m 3 to 15.7 kN/m 3 with moisture contents
ranging from about 18 to 33%. Given the results of the laboratory tests, the
measured densities were calculated to be 73 to 82% of the maximum dry density
determined in the laboratory.
A review of daily field reports from construction indicates that the fill was
placed and compacted to at least 95% of the maximum dry density in accordance
with a modified proctor with resulting field dry densities of at least 16.2 kN/m 3 .
During excavation it was noted that the thickness of the stone drainage
material behind the block facing was highly variable, ranging from the design
thickness of 1.2 m to less than 0.3m. At several locations thin layers of soil
intruded into the drainage material such that water would not be permitted to
drain freely to the collection system and outlet pipes at the base of the wall.
Excavation of the stormwater pipe extending from the concrete drop inlet at
the failure location revealed that this reinforced concrete pipe was not
constructed with rubber gaskets or other sealing materials. Furthermore,