Date of Award

5-2009

Degree Type

Report

Degree Name

Master of Science (MS)

Department

Civil and Environmental Engineering

First Advisor

John D. Rice

Second Advisor

Joe Caliendo

Third Advisor

Paul Barr

Abstract

Seepage barriers are commonly installed in earthen dams and levees all over the world and consist of slurry walls, concrete walls, jet grouted walls, secant pile walls, sheet pile walls, and deep soil mixed walls. The purpose of the barrier is to reduce the amount of flow and seepage through the embankment and the foundation of the dam or levee. When seepage barriers were first being used it was under the impression that barriers would be a permanent mitigation of seepage problems. However, in prior research (Rice, 2007) it is mentioned that there are several cases where the seepage barriers did not perform as expected, concluding that there may be failure mechanisms that are unique to each seepage barrier. When a crack is introduced to the seepage barrier, in some cases internal erosion may be taking place causing the crack to widen. As the crack gets wider the flow through that crack may increase until a point when the soil controls the amount of flow into the crack or soil starts to fill the crack.

This study compares theoretical values vs. measured values of flow and head readings using a laboratory test cell for the measured values and a finite element analysis computer program for theoretical. Also looked at is the interaction of the sand and the crack for variables of flow and erosion. Taken into account are variables for crack type (smooth and fractured), crack aperture, and the hydraulic conductivity of the sand placed around the seepage barrier. This is done by modeling the crack through a seepage barrier test cell for different apertures and different head values.

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