Date
08 May 1984, 10:15 am - 5:00 pm
Abstract
Landslides occurred in the Bearpaw shale slope adjacent to the powerhouses at Fort Peck Dam in the geologic past. Excavation of the slope toe for construction of reservoir outlet works in 1934 initiated progressive sliding of colluvium which continued to 1974. The active slide area had an average movement rate of 4 ft/yr from 1944-1945 and average movement rates of 1-2 ft/yr from 1953-1971. These movements caused no distress to the powerhouses or other facilities. In 1974, the slope was stabilized by excavating 1.6 x 106 cu. yd. of material, resulting in a 1 on 6 overall slope. A field residual strength given by c' = 0.1 ksf, Φ' = 10° or c' = 0, Φ' = 11.5° for effective normal stresses of 3-4 ksf was calculated from the slides using 1950's topography and groundwater levels.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
1st Conference of the International Conference on Case Histories in Geotechnical Engineering
Publisher
University of Missouri--Rolla
Document Version
Final Version
Rights
© 1984 University of Missouri--Rolla, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Hamel, J. V. and Spencer, G. S., "Powerhouse Slope Behavior, Fort Peck Dam, Montana" (1984). International Conference on Case Histories in Geotechnical Engineering. 29.
https://scholarsmine.mst.edu/icchge/1icchge/1icchge-theme3/29
Powerhouse Slope Behavior, Fort Peck Dam, Montana
Landslides occurred in the Bearpaw shale slope adjacent to the powerhouses at Fort Peck Dam in the geologic past. Excavation of the slope toe for construction of reservoir outlet works in 1934 initiated progressive sliding of colluvium which continued to 1974. The active slide area had an average movement rate of 4 ft/yr from 1944-1945 and average movement rates of 1-2 ft/yr from 1953-1971. These movements caused no distress to the powerhouses or other facilities. In 1974, the slope was stabilized by excavating 1.6 x 106 cu. yd. of material, resulting in a 1 on 6 overall slope. A field residual strength given by c' = 0.1 ksf, Φ' = 10° or c' = 0, Φ' = 11.5° for effective normal stresses of 3-4 ksf was calculated from the slides using 1950's topography and groundwater levels.
