Failure of an 8-Meter-High Segmental Block Wall in the Northeast United States - Reinforced Soil Engineering: Advances in Research and Practice - page 118

indicated that the backfill soils did not meet the projects requirements. However,
even though the compaction was less than specified, the laboratory testing
showed effective friction angles close to the values used in the original design.
Thus, this alone is not considered to be the only cause of failure. The poor
compaction resulted in a higher void ratio, which could have affected the
permeability. Also, the in-situ moisture contents measured after the wall failure
were much higher than those reported during construction.
Several combined construction deficiencies are suspected to have caused
the failure. Compaction was performed within the reinforced zone using a small
walk behind vibratory sheepsfoot roller. Dry densities measured after the wall
failure generally agreed with the dry densities reported during construction.
Therefore, the wrong proctor was likely referenced during construction, which
showed compaction meeting the specification when in fact the relative degree of
compaction was very low. Poor construction of the storm drain introduced
additional water into the wall backfill, and the soil intrusion into the drainage
stone behind the wall reduced its effectiveness.
REFERENCES
JG Collin,ed. Design Manual for Segmental Retaining Walls. Herndon: National Concrete
Masonry Association, 1997.
U.S. Department of Transportation, Federal Highway Administration, PC-STABL6 Users'
Guide, Slope Stability Analysis Program. McLean: Turner-Fairbank Highway
Research Center, 1986.
HW Van Aller. STED 6.5 PCSTABL Editor. Queenstown: H. W. Van Aller, 1996.