Location

St. Louis, Missouri

Session Start Date

3-11-1991

Session End Date

3-15-1991

Abstract

The U.S. Army Corps of Engineers recently completed a seismic stability assessment of the Ririe Darn and Reservoir Project located near Idaho Falls, Idaho. Ririe Darn is an earth- and rockfill darn with a central impervious core constructed between 1966 and 1975 in a narrow canyon of Willow Creek. A geologic and seismologic study indicated that the controlling maximum credible earthquake (MCE} is a Magnitude 7.5 earthquake at a distance of 8 km from the darn. The seismic stability analysis included a dynamic response analysis of the darn using two-dimensional finite element procedures. Empirical relations derived from the observed response and analyses of other darns in narrow canyons were used to develop adjustment factors to correct natural frequencies, dynamic shear stresses, and peak accelerations for three-dimensional (3-D} effects. The October 28, 1983 Mt. Borah Earthquake triggered five strong-motion instruments installed at the crest, left abutment, downstream toe, and outlet tower of Ririe Darn. The epicentral distance to the darn was 179 km. The peak horizontal accelerations recorded at the crest and at the abutment were 0.05 g and 0.02 g, respectively. The accelerogram recorded by the instrument station at the abutment was used to calculate the dynamic response of the darn during the earthquake. From this analysis, the finite element model and the soil parameters were calibrated to best represent the 3-D dynamic response of the darn. After consideration of 3-D effects, the calculated response of the darn using soil properties derived from in-situ and laboratory measurements was in good agreement with the measured response during the 1983 Mt. Borah earthquake. These results indicate that when properly applied, currently available methods to determine soil properties for the dynamic response analysis of embankment darns including in-situ measurements, can provide properties in good agreement with those back-calculated from the observed response of darns.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Second Conference

Publisher

University of Missouri--Rolla

Publication Date

3-11-1991

Document Version

Final Version

Rights

© 1991 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 11th, 12:00 AM Mar 15th, 12:00 AM

Measured and Calculated Dynamic Response of Rock-Fill Dam

St. Louis, Missouri

The U.S. Army Corps of Engineers recently completed a seismic stability assessment of the Ririe Darn and Reservoir Project located near Idaho Falls, Idaho. Ririe Darn is an earth- and rockfill darn with a central impervious core constructed between 1966 and 1975 in a narrow canyon of Willow Creek. A geologic and seismologic study indicated that the controlling maximum credible earthquake (MCE} is a Magnitude 7.5 earthquake at a distance of 8 km from the darn. The seismic stability analysis included a dynamic response analysis of the darn using two-dimensional finite element procedures. Empirical relations derived from the observed response and analyses of other darns in narrow canyons were used to develop adjustment factors to correct natural frequencies, dynamic shear stresses, and peak accelerations for three-dimensional (3-D} effects. The October 28, 1983 Mt. Borah Earthquake triggered five strong-motion instruments installed at the crest, left abutment, downstream toe, and outlet tower of Ririe Darn. The epicentral distance to the darn was 179 km. The peak horizontal accelerations recorded at the crest and at the abutment were 0.05 g and 0.02 g, respectively. The accelerogram recorded by the instrument station at the abutment was used to calculate the dynamic response of the darn during the earthquake. From this analysis, the finite element model and the soil parameters were calibrated to best represent the 3-D dynamic response of the darn. After consideration of 3-D effects, the calculated response of the darn using soil properties derived from in-situ and laboratory measurements was in good agreement with the measured response during the 1983 Mt. Borah earthquake. These results indicate that when properly applied, currently available methods to determine soil properties for the dynamic response analysis of embankment darns including in-situ measurements, can provide properties in good agreement with those back-calculated from the observed response of darns.