Alternative Title

Paper No. 2.43

Location

St. Louis, Missouri

Session Start Date

3-8-1998

Session End Date

3-15-1998

Abstract

An inspection of Ivins Bench dam and reservoir was performed following a 5.8 magnitude (Mw) earthquake in southern Utah. Sand was observed flowing from the drainage collection system and the Utah Division of Dam Safety requested that the reservoir be drained and the embankment repaired. Dames & Moore evaluated the liquefaction potential of the embankment and concluded that the embankment was not suitable for maximum storage. A repair concept using a soil-cement mix wall was developed and a dynamic stability analysis was performed using the computer program PLAC. The dynamic analysis indicated that the soil-cement wall would improve embankment stability and significantly lower the phreatic surface downstream of the wall, thus reducing the liquefaction potential. One hundred and fourteen (114) soil-cement panels (6.83-feet wide and 34-inches thick) ranging from 18 to 50 feet in depth were installed parallel to the upstream crest of the embankment. The panels penetrated 3-feet into the bedrock underlying the embankment. Subsequent to construction, a 36-inch diameter outlet pipe was installed through both the embankment and soil-cement mix wall by microtunneling methods. A new intake structure was also constructed. Construction began in January, 1996 and the reservoir was filled during spring 1997 runoff.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-8-1998

Document Version

Final Version

Rights

© 1998 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Seismic Evaluation, Soil-Cement Mix Wall and Outlet Pipe Installation, Ivins Bench Dam, Utah

St. Louis, Missouri

An inspection of Ivins Bench dam and reservoir was performed following a 5.8 magnitude (Mw) earthquake in southern Utah. Sand was observed flowing from the drainage collection system and the Utah Division of Dam Safety requested that the reservoir be drained and the embankment repaired. Dames & Moore evaluated the liquefaction potential of the embankment and concluded that the embankment was not suitable for maximum storage. A repair concept using a soil-cement mix wall was developed and a dynamic stability analysis was performed using the computer program PLAC. The dynamic analysis indicated that the soil-cement wall would improve embankment stability and significantly lower the phreatic surface downstream of the wall, thus reducing the liquefaction potential. One hundred and fourteen (114) soil-cement panels (6.83-feet wide and 34-inches thick) ranging from 18 to 50 feet in depth were installed parallel to the upstream crest of the embankment. The panels penetrated 3-feet into the bedrock underlying the embankment. Subsequent to construction, a 36-inch diameter outlet pipe was installed through both the embankment and soil-cement mix wall by microtunneling methods. A new intake structure was also constructed. Construction began in January, 1996 and the reservoir was filled during spring 1997 runoff.