There are many experimental relations that would be utilized to convert Lu values (typically between 1 to 100) to Permeability values as follows; 1- K (m/sec) = (5.9918e-8)*N*LOG10(L/r) (Richter and Lillich, 1975) 2- K (m/sec) = (1e-7)*N (Barton and Quadros, 2003) 3- K (m/sec) = (1.635e-7)*N (Fransson, 2004) where K, N, L and r are respectively permeability, Lugeon value, length of test section and radius of borehole. You should note to this point that the Lugeon values are strongly affected by hydraulic aperture of rock fractures and also the effective radius. Unfortunately, we don't have slightest idea about them exactly because the Lugeon test is a single well test. I have proposed the following equation considering this problem; 4- Ku (m/sec) = (5.9918e-8)*N (Karbala, 2008 - in Persian) where Ku means the permeability according to given assumption LN(re/r)=1. So, we could call Ku as "the permeability of unit neperian logarithm of re/r".Note that "re" is effective radius of test. In the equations of 1 to 3, re is assumed to be equal to another values. For example in equation (1), re is assumed to be equal to section length (L). So, as a final exam (!); which equation do you opt for estimation of permeability?

Taller sheet pile walls will need a tie-back anchor, or "dead-man" placed in the soil a distance behind the face of the wall, that is tied to the wall, usually by a cable or a rod. Anchors are placed behind the potential failure plane in the soil.

The permeability of a rock in Lugeon unit is calculated and the corresponding permeability in Lefranc method (i.e. say in cm/sec) is needed. Here the equation for that is given how it is converted into another.