Partial reburial of West Ruin at Aztec Ruins National Monument

Abstract

Aztec Ruins National Monument is a World Heritage Site in northwestern New Mexico, USA. More than 50,000 visitors come to the site each year, specifically to visit West Ruin, a 12th–13th century, multi-storey Ancestral Pueblo an (Anasazi) village with over 400 rooms. West Ruin was excavated in the early 1900s and was intentionally left exposed for public access and interpretation. The walls, constructed of shaped sandstone blocks set in mud mortar, have gradually deteriorated, despite years of stabilization and preservation efforts. In 1999, park management began to partially rebury portions of West Ruin as a reversible long-term preservation treatment. While partial reburial allows for presentation of the site to visitors, it also results in uneven fill levels in many rooms. Differential fill levels can increase the area subject to migration and capillary rise of moisture through the walls, and can accelerate stone and mortar deterioration on the exposed wall faces. Differential fill levels can also lead to structural instability from unequal pressure exerted between filled and non-filled areas. To mitigate moisture migration and structural instability from differential fills, a soil retention system was designed and tested using layers of synthetic three-dimensional earth confinement cells. This paper discusses the design and implementation of the soil retention system within the larger context of a multi-phased reburial project underway at Aztec Ruins National Monument.