Geosynthetics in roads and pavements

ENVIRONMENTAL PROTECTION 

SYSTEMS 

 

Introduction to the Problem  

 The increase in environmental sensitivity of the 

last two decades has led to important regulations 

requiring “de minimus” leakage of 

contamination to the environment from landfills 

and other waste deposits.  Additionally, as soon 

as a landfill reaches capacity, it must be capped 

to minimize future leachate generation  

Typical Solutions 

Conventional Systems. To minimize liquid 

migration, conventional capping and lining 

systems often include: 

1.  very low permeability soil barrier layers 

such as thick layers of silts and clays,  

2.  drainage layers of coarse uniformly graded

 

sands or gravels, and  

3.  specially graded sand filters.  

Where readily available, clay can be compacted 

in multiple layers to achieve a durable, very low 

permeability barrier.  Yet, the integrity of clay 

barriers is adversely effected by:  

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variations in texture (i.e. presence of clods),  

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fluctuating moisture content and compaction 

effort,  

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extreme temperature exposure, and  

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exposure to certain chemicals.  

Gravel and sand layers, if locally available, can 

be cost-effectively engineered into systems to 

collect and remove liquids and gasses.  Yet, 

assuring proper gradations, facilitating 

placement on slopes, and obtaining uniform 

layer thickness often requires large construction 

tolerances and numerous inspections.