Location

St. Louis, Missouri

Session Start Date

4-26-1981

Session End Date

5-3-1981

Abstract

The Spinney Mountain Dam, now under construction in central Colorado, is a zoned earth embankment with a maximum height of 95 feet above foundation. Detailed geological investigations revealed rejuvenated sediments of nearby older faults, which have undergone tectonic movement within the past 13,000 to 30,000 years and hence are considered capable. Studies indicate the largest earthquake expected on the controlling fault would have a Richter Magnitude of about 6.2, implying peak ground accelerations at the site of about 0.6g and a 15-second duration of strong motion. Displacement on a branch of the main capable fault during such an event is estimated at four to six inches. Slope deformation analyses estimate a movement at the crest of the dam of not more than two inches horizontally and considerably less vertically, which would not result in a significant decrease in strength of the compacted soils. Reservoir induced seismicity is not considered to be a hazard.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

First Conference

Publisher

University of Missouri--Rolla

Publication Date

4-26-1981

Document Version

Final Version

Rights

© 1981 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 26th, 12:00 AM May 3rd, 12:00 AM

Seismic Analysis of Spinney Mountain Dam

St. Louis, Missouri

The Spinney Mountain Dam, now under construction in central Colorado, is a zoned earth embankment with a maximum height of 95 feet above foundation. Detailed geological investigations revealed rejuvenated sediments of nearby older faults, which have undergone tectonic movement within the past 13,000 to 30,000 years and hence are considered capable. Studies indicate the largest earthquake expected on the controlling fault would have a Richter Magnitude of about 6.2, implying peak ground accelerations at the site of about 0.6g and a 15-second duration of strong motion. Displacement on a branch of the main capable fault during such an event is estimated at four to six inches. Slope deformation analyses estimate a movement at the crest of the dam of not more than two inches horizontally and considerably less vertically, which would not result in a significant decrease in strength of the compacted soils. Reservoir induced seismicity is not considered to be a hazard.