Soil, earth construction: Wacker WP 1550 manually operated walk-behind vibratory plate compactor compacting soil fill behind retaining wall. Geotech fabric covers back side of retaining wall. In distance is nuclear guage and technician that measures density of compacted soil. To right is unexcavated earth embankment. Fill will be placed up to top of retaining wall, compacted in lifts specified by design, probably 6, 8, or 12 inches. Huron Parkway, Ann Arbor, 2005.