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					Opportunity for a Bachelor or M. Sc. thesis work:
Evaluation of hydraulic conductivity by comparison of three different methods
Background: Hydraulic conductivity or permeability is a measure of the ability of water to
move through a material. About 80 million tons of mine waste is produced in Sweden each
year. Environmental authorities in Sweden require remediation methods that function over
long time periods without maintenance. To reduce the amount of oxygen reaching the
sulphides in the mining waste a type of soil cover can be applied. Soil covers usually contain
a sealing layer with low hydraulic conductivity. This is important since a material with low
hydraulic conductivity will prevent water and oxygen from passing through the cover and
therefore reducing the risk of leaching and contaminating the environment.

Task: You will evaluate the hydraulic conductivity of a material that potentially can be used
as a sealing layer for mine waste.
You will compare three different methods of determining hydraulic conductivity and see how
the results differ.

One method is the Constant Head Permeability (CHP) test. This is a test where you allow
water to pass through the material under a steady state head condition while measuring the
quantity of water flowing through the material over a period of time. Hydraulic conductivity
can in this way be calculated applying Darcy’s law.

Another method is the Constant Rate of Strain (CRS) test. The material is deformed with a
force during a certain time while the pore pressure is measured. Hydraulic conductivity is
calculated based on the rate of deformation and the pore pressure.

The third method is calculating the hydraulic conductivity using grain size analysis.

Researchers often use only one test for hydraulic conductivity and assume it is accurate.
This study is of great importance since it will provide a guideline directed towards whether or
not the tests can work independently.

The report can be written in Swedish or in English.

Contact person :

Kerstin.Pousette@ltu.se Samhällsbyggnad Rum: F1071 Tel: 0920-491909

maria.mäkitalo@ltu.se Tillämpad kemi & geovetenskap Rum: F835a Tel: 0920-492830

				
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posted:11/11/2011
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