Citation

Munoz A, Gano D. Transp. Res. Rec. 1974; 482: 1-8.

Copyright

(Copyright © 1974, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The reliability and usefulness of field instrumentation in providing design data for landslide correction are clearly illustrated in the case history of the Fountain landslide. The area known as the Fountain Slide affects an approximately 3/4-mile (1-km) section of I-80N just north of Mt. Hood about 45 miles (72 km) east of Portland, Oregon. This section of highway is flanked on one side by a railroad and the Columbia River and on the other side by the ancient landslide, which extends for several thousand feet (more than 1 km) to a sheer rock face some hundreds of feet (more than 200 m) above the lower slopes. Construction of I-80N required cutting into the unstable area a substantial distance and resulted in increased slide activity. Since the construction of the Interstate, several efforts have been made to stabilize the Fountain Slide. None have been totally successful, largely because the cause of the failure was not fully understood. In 1968 field instrumentation was installed that made it possible to carefully define the failure surface and actual groundwater conditions. This information was used to design a slide correction scheme. Construction of a 3.2-million- dollar correction scheme, which was scheduled to start in the early spring of 1973, has been delayed by further areal extension of the slide mass. The instrumentation program has been expanded to include the new unstable area. The feasibility of relocating the highway into the Columbia River or a do-nothing alternative with continued maintenance and a warning system are also being studied. The field instrumentation is being continually monitored to ensure proper design input for whatever remedy is selected.