Location

New York, New York

Session Start Date

4-13-2004

Session End Date

4-17-2004

Abstract

A soil-bentonite slurry trench cutoff wall was installed as part of landfill improvements at the Macon County Landfill located in Decatur, Illinois. In order for a soil-bentonite barrier to be continuous and defect-free, a homogeneous, well-graded backfill needs to displace the slurry used to maintain trench stability. Historically, specifications required that the backfill have a unit weight of 15 pounds per cubic foot (pcf) higher than the unit weight of the in-trench slurry and the slurry have a maximum density of 85 pcf. More recently, specifications have also required that the sand content of the slurry, not exceed 10 to 15%. During the course of construction, difficulties arose which gave rise to post-construction investigations of the integrity of the completed cutoff wall. A program of field sampling and testing, which included Osterberg sampling, modified Osterberg sampling, and sonic-core borings, was developed to investigate the integrity of the wall. Since state-of-the-practice quality assurance and quality control measures are based upon field measurements and sampling during construction coupled with laboratory measurements of field-prepared backfill samples, detailed investigations of the in-situ, as-constructed wall are relatively uncommon and even more uncommonly documented in the literature. This paper presents these investigations, findings, conclusions derived from the investigations and provides recommendations for slurry wall design and construction derived from these studies.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fifth Conference

Publisher

University of Missouri--Rolla

Publication Date

4-13-2004

Document Version

Final Version

Rights

© 2004 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 13th, 12:00 AM Apr 17th, 12:00 AM

Lessons Learned from the Macon County Slurry Wall

New York, New York

A soil-bentonite slurry trench cutoff wall was installed as part of landfill improvements at the Macon County Landfill located in Decatur, Illinois. In order for a soil-bentonite barrier to be continuous and defect-free, a homogeneous, well-graded backfill needs to displace the slurry used to maintain trench stability. Historically, specifications required that the backfill have a unit weight of 15 pounds per cubic foot (pcf) higher than the unit weight of the in-trench slurry and the slurry have a maximum density of 85 pcf. More recently, specifications have also required that the sand content of the slurry, not exceed 10 to 15%. During the course of construction, difficulties arose which gave rise to post-construction investigations of the integrity of the completed cutoff wall. A program of field sampling and testing, which included Osterberg sampling, modified Osterberg sampling, and sonic-core borings, was developed to investigate the integrity of the wall. Since state-of-the-practice quality assurance and quality control measures are based upon field measurements and sampling during construction coupled with laboratory measurements of field-prepared backfill samples, detailed investigations of the in-situ, as-constructed wall are relatively uncommon and even more uncommonly documented in the literature. This paper presents these investigations, findings, conclusions derived from the investigations and provides recommendations for slurry wall design and construction derived from these studies.