Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

The paper presents the results of the geotechnical evaluation of the existing conditions of the local flood protection of Topeka, the state capital of Kansas. The existing levee system constructed by the U.S. Army Corps of Engineers consists of 6 levees units along the north and south bank of the Kansas River and tributaries, Soldier Creek and Shunganunga Creek. The geotechnical evaluation of the existing conditions of the levee system was based on all available geotechnical data and on the past performance of the system. The critical reaches of each levee unit were identified based on the geotechnical conditions and levee geometry. The geotechnical levee system response to river stage loading was evaluated. Geotechnical information included subsurface investigation performed for the design and construction of the levee, geotechnical information obtained for subsequent levee modification, and cone penetrometer tests and laboratory testing performed on selected samples collected from additional borings drilled in areas considered critical or known to experience excessive underseepage during previous flooding events. Uncertainty analyses were performed to define the existing condition of the Topeka Levee System. The system response was determined by evaluating the foundation and embankment materials and assigning values for the probability moments of the random variables considered in the analyses. The performance functions considered for the risk analyses were slope stability and underseepage piping stability. The internal erosion due to seepage through the embankment was not considered, the levee embankments being constructed of cohesive fill. A set of conditional-probability-of-failure versus floodwater-elevation graphs were developed as related to underseepage piping stability and slope stability for the long-term seepage. Reliability analysis was performed using Taylor’s Series Method. In the Taylor method, random variables were quantified by their expected mean values, standard deviations, and correlation coefficients.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Sixth Conference

Publisher

Missouri University of Science and Technology

Publication Date

8-11-2008

Document Version

Final Version

Rights

© 2008 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Aug 11th, 12:00 AM Aug 16th, 12:00 AM

Geotechnical Risk Analysis of the Local Flood Control Projects on the Kansas River in Topeka, Kansas

Arlington, Virginia

The paper presents the results of the geotechnical evaluation of the existing conditions of the local flood protection of Topeka, the state capital of Kansas. The existing levee system constructed by the U.S. Army Corps of Engineers consists of 6 levees units along the north and south bank of the Kansas River and tributaries, Soldier Creek and Shunganunga Creek. The geotechnical evaluation of the existing conditions of the levee system was based on all available geotechnical data and on the past performance of the system. The critical reaches of each levee unit were identified based on the geotechnical conditions and levee geometry. The geotechnical levee system response to river stage loading was evaluated. Geotechnical information included subsurface investigation performed for the design and construction of the levee, geotechnical information obtained for subsequent levee modification, and cone penetrometer tests and laboratory testing performed on selected samples collected from additional borings drilled in areas considered critical or known to experience excessive underseepage during previous flooding events. Uncertainty analyses were performed to define the existing condition of the Topeka Levee System. The system response was determined by evaluating the foundation and embankment materials and assigning values for the probability moments of the random variables considered in the analyses. The performance functions considered for the risk analyses were slope stability and underseepage piping stability. The internal erosion due to seepage through the embankment was not considered, the levee embankments being constructed of cohesive fill. A set of conditional-probability-of-failure versus floodwater-elevation graphs were developed as related to underseepage piping stability and slope stability for the long-term seepage. Reliability analysis was performed using Taylor’s Series Method. In the Taylor method, random variables were quantified by their expected mean values, standard deviations, and correlation coefficients.