Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

Vertical containment walls have been used as barriers to cut off hazardous fluid and chemical flow in the ground at contaminated sites. An application of this technique in South Carolina is to construct a 1.6-mile long containment wall along a dike using cement-bentonite slurry, which features low permeability and high compressive strength. However, concerns about the stability of the cement-bentonite slurry trench have been raised because an existing soil-bentonite wall will be in very close proximity to the alignment of the cement-bentonite slurry trench; and the shear strength of the existing soil bentonite backfill is considered to be low. Excessive overbreak of the new trench sidewalls is anticipated during construction. Utilizing the data obtained from the geotechnical borings drilled on the dike and CPT results, a parametric study was carried out in order to establish the minimum distance between the cement-bentonite slurry trench and the existing soil-bentonite backfill. Different cases were analyzed according to the strength parameters of the soil-bentonite backfill and the water level of the pond. In this paper the authors present the method and results of the stability analyses of the cement-bentonite slurry trench against wall collapsing. The calculated factor of safety with varying soil-bentonite backfill friction angles is plotted as function of the distance to the proposed trench. The results are discussed and recommendations are given to minimize the probability of trench overbreak. As a means to monitor the stability of the dike, inclinometers were installed prior to trench excavation. With the new trench being advanced, the measurements from the inclinometers show the movement of the dike due to trenching. These data are also discussed in the paper.

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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Slurry Trench Stability Analysis – Constructing Cement-Bentonite Slurry Trench Adjacent to Existing Soil-Bentonite Backfill

Arlington, Virginia

Vertical containment walls have been used as barriers to cut off hazardous fluid and chemical flow in the ground at contaminated sites. An application of this technique in South Carolina is to construct a 1.6-mile long containment wall along a dike using cement-bentonite slurry, which features low permeability and high compressive strength. However, concerns about the stability of the cement-bentonite slurry trench have been raised because an existing soil-bentonite wall will be in very close proximity to the alignment of the cement-bentonite slurry trench; and the shear strength of the existing soil bentonite backfill is considered to be low. Excessive overbreak of the new trench sidewalls is anticipated during construction. Utilizing the data obtained from the geotechnical borings drilled on the dike and CPT results, a parametric study was carried out in order to establish the minimum distance between the cement-bentonite slurry trench and the existing soil-bentonite backfill. Different cases were analyzed according to the strength parameters of the soil-bentonite backfill and the water level of the pond. In this paper the authors present the method and results of the stability analyses of the cement-bentonite slurry trench against wall collapsing. The calculated factor of safety with varying soil-bentonite backfill friction angles is plotted as function of the distance to the proposed trench. The results are discussed and recommendations are given to minimize the probability of trench overbreak. As a means to monitor the stability of the dike, inclinometers were installed prior to trench excavation. With the new trench being advanced, the measurements from the inclinometers show the movement of the dike due to trenching. These data are also discussed in the paper.