What do you need the permeability values for?

@jmcc3265 I need the permeability value for landfill design. I tested few samples mix between clay to get the lowest coefficient value, then I came across that there are some different formula to determined the k value.

We perform remolded falling-head tests in the Florida panhandle for retention pond design. We encounter primarily poorly graded fine sands [SP, SP-SM] in our area. We use the formula: k=2.303(aL/At) 〖log〗_10 (h_1/h_2)

Remolded samples, in my opinion, are not real accurate. I sometimes push tubes to perform permeability testing on; however, it is difficult to obtain an 'undisturbed' sample of sandy material.

You can also find relationships for hydraulic conductivity for cohesive and granular soils in most geotechnical textbooks. These relationships use void ratio, and grain size and gradation to estimate the hydraulic conductivity. I would not use these for design though.

You probably should follow an ASTM standard.

http://www.astm.org/Standards/D5084

Thanks guys!