Settlement of Shallow Foundations on Uncontrolled Mine Spoil Fill

The project consists of a five-building motel facility, constructed on a previously mined site in eastern Kentucky. Two geotechnical engineering investigations of the site failed to identify the depth of mine spoil on the site. The first geotechnical engineer recommended the total removal of the uncontrolled mine spoil from beneath the buildings. The second geotechnical engineer recommended only partial removal of the mine spoils directly beneath the footings. The project participants ultimately adopted the second approach for construction and, before completion of the project, settlements of about 0.5 m rendered building 1 unusable. Within five years, building 1 settled about 1 m. In addition, the west end of building 2 had settled about 300 mm. The project developers hired the writer to determine the cause of the settlement and provide testimony in the case. This paper presents the site and project histories, a description of the writer's investigation, a discussion of the results, a description of the dispute resolution processes used for the case, and the writer's suggested procedural changes.