Compressibility and hydraulic conductivity of sand-attapulgite cut-off wall backfills

Soil-bentonite cut-off walls have been used widely to control pollution in landfills but their antifouling property (their ability to prevent contaminants in landfills from polluting the surrounding environment) decreases significantly over time due to a variety of factors (e.g. contaminant concentr...

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Bibliographic Details
Published in:Journal of Zhejiang University. A. Science 2019-03, Vol.20 (3), p.218-228
Main Authors: Zhang, Wen-bing, Rao, Wen-bo, Li, Lei, Liu, Ye, Wang, Shuai, Jin, Ke, Zheng, Fang-wen
Format: Article
Language:English
Subjects:
Antifouling substances
Backfill
Bentonite
Civil Engineering
Classical and Continuum Physics
Compressibility
Compression
Consolidation
Contaminants
Engineering
Hydraulic conductivity
Hydraulics
Industrial Chemistry/Chemical Engineering
Landfill
Landfills
Mathematical analysis
Mechanical Engineering
Pollution control
Sand
Soil compressibility
Soil contamination
Soil pollution
Test procedures
Walls
Waste disposal sites
Weight
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Summary:Soil-bentonite cut-off walls have been used widely to control pollution in landfills but their antifouling property (their ability to prevent contaminants in landfills from polluting the surrounding environment) decreases significantly over time due to a variety of factors (e.g. contaminant concentrations). In recent years, attapulgite has been considered as a backfill material for cut-off walls, but relevant studies are lacking. In this study, the compressibility and hydraulic conductivity of sand-attapulgite backfills were investigated using consolidation and hydraulic conductivity tests. In these tests, attapulgite comprised 10%, 20%, 30%, 40%, 60%, 80%, or 100% (dry weight) of the backfills. The results showed that (1) the compression ( C c ) and swell ( C s ) indexes of the backfills increased linearly with increasing attapulgite content ( A p ); (2) both the consolidation coefficient ( C v ) calculated by the Casagrande and Taylor methods and the hydraulic conductivity ( k theory ) calculated according to Terzaghi consolidation theory decreased with increasing attapulgite content. In the case of an effective consolidation stress σ′
ISSN:1673-565X
1862-1775
DOI:10.1631/jzus.A1800548