In late February, 2003, a steep hillside behind three apartment buildings near Nashville, Tennessee displayed signs of instability. Evidence of movement was noted as small bulges emerged in various places along the slope. In the following days, additional movement was observed and the residents from 70 units were evacuated and relocated. A geotechnical review confirmed that the physical symptoms were indicative of a landslide. Closer inspection revealed tension cracks developing several hundred feet up the slope and extending laterally approximately 500 feet resulting in an active slide area of about 6 acres with less than 20 feet of clearance between the moving slope and remaining unoccupied apartments. Data derived from slope inclinometers recorded movements up to 35 feet deep and surveys confirmed that the scarp occurred at least 450 feet up the slope crossing well over the property line. Due to property line constraints, the repair was restricted to the lower half of the active
slide area. As spring rains intensified and the slide movement accelerated, the design-build retention system was converted to a build-design system as the construction moved to a fast-track schedule. An anchored soldier beam and lagging wall was constructed to create the first line of
defense. The permanent repair scheme included an initial installation of the anchored soldier beam and lagging wall augmented by two rows of reaction blocks and anchors located upslope of the wall. As the movement of the slope slowed in response to the initial repairs, some surface grading was performed and surface ditches were constructed to divert surface water from the lower landslide mass to further enhance slide stability.
This paper will cover the emergency action plan, an overview of the design considerations, challenging aspects of the construction and the unique and complicated relationships developed between multiple owners, property managers, designers, peer reviewers, adjacent property owners and the contractor.