Lefranc and Lugeon correlations 1

[cmorgh]

Hi,
I am searching for a correlation between the permeability values obtained by Lefranc and Lugeon field tests. In other words, the permeability of a rock in Lugeon unit is calculated (upon completion of a Lugeon test) and the corresponding permeability in Lefranc method (i.e. say in cm/sec) is needed.

Thanks
Cmorgh

 

[BigHarvey]

Lugeon tests are exclusively performed in rock and Lefranc tests exclusively in soils. I doubt very much that a correlation between the two exist and if it exists what does it mean ? You would be better off sticking to the appropriate test in relation to the material you are working in.

 

[cmorgh]

BigHarvey
You are right. Lugeon is expected to be performed in rock, whilst lefranc is expected to be performed in alluvium.
However, consider that the alluvial layer is grouted now (Lefranc being performed prior to grouting). The layer is now different from alluvium and mostly similar to rock (packer set up easily carried out after drilling). Hence, Lugeon is performed. Now, how to correlate these two results?

 

[BigHarvey]

Instead of trying to use correlations which, to my knowledge, do not exist, why wouldn't you use test procedures derived from Lefranc test, specially adapted for very low permeability materials.
One example is Lefranc test carried out with compressed air instead of water. It is used to check the permeability of slurry walls used as confinement barriers.
A very comprehensive textbook has been written by Maurice CASSAN ( in french ) "Les essais d'eau dans la reconnaissance des sols".
You can also search on the web for permeability tests in slurry walls.