Session Start Date

5-6-1984

Abstract

This paper describes the results of an extensive investigation made to determine the cause of excessive settlements of two 800 MN steam turbine units located at the Four Corners Steam Electric Station near Farmington, New Mexico. The units are located on a clay-shale formation with numerous gypsum seams. The settlement was originally attributed to the solutioning of these gypsum seams. It was found that the construction of a large unlined cooling pond raised the ground water table in the vicinity of the power plant. In this saturated environment, a chemical attack of the existing clay shales began. It is believed that the chemical reaction causing the degradation of the clay-shale has been identified and that a chemical solution to the problem has been found. The reaction involves the removal of the exchangeable cation from the clay lattice, which goes into solution. As the cations are leached out, the clays tend to weather toward the montmorillonite end of the transformation series.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

First Conference

Publisher

University of Missouri--Rolla

Publication Date

5-6-1984

Document Version

Final Version

Rights

© 1984 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 6th, 12:00 AM

A Case History of Chemical Attack of a Clay Shale

This paper describes the results of an extensive investigation made to determine the cause of excessive settlements of two 800 MN steam turbine units located at the Four Corners Steam Electric Station near Farmington, New Mexico. The units are located on a clay-shale formation with numerous gypsum seams. The settlement was originally attributed to the solutioning of these gypsum seams. It was found that the construction of a large unlined cooling pond raised the ground water table in the vicinity of the power plant. In this saturated environment, a chemical attack of the existing clay shales began. It is believed that the chemical reaction causing the degradation of the clay-shale has been identified and that a chemical solution to the problem has been found. The reaction involves the removal of the exchangeable cation from the clay lattice, which goes into solution. As the cations are leached out, the clays tend to weather toward the montmorillonite end of the transformation series.