Reliability of Nuk Density Testing in Exploration Test Pits
Reliability of Nuk Density Testing in Exploration Test Pits
(OP)
My question for the honorable forum is this: Does anyone have an opinion regarding the reliability of using a nuclear density probe device to obtain indications of density within a soil exploration test pit? We typically use them in ours within the upper 4 to 5 feet but have not heard of any liability issues associated with making judgements on density using this approach as opposed to other methods such as visual (caving=loose)or driving resistance like a Dynamic Penetrometer. Any thoughts or comments?





RE: Reliability of Nuk Density Testing in Exploration Test Pits
RE: Reliability of Nuk Density Testing in Exploration Test Pits
RE: Reliability of Nuk Density Testing in Exploration Test Pits
I have used this several times - as early as about 1990. (I'm pretty sure that it's been around for more than 14 years, though.) I have compared the results to lab moistures and sand cone densities - they compare as well as "level" ground tests. At least in my experience.
If you are concerned, run sand cones on 25% of the in trench densities for comparison and QA/QC. This will also give you confidence in the machine results -
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: Reliability of Nuk Density Testing in Exploration Test Pits
RE: Reliability of Nuk Density Testing in Exploration Test Pits
I remember over the penetration depth of the DCP, we were able to correlate a bearing capacity directly from the blow counts, given a weighted average over the entire depth. It seems to me there was a some science other than the spreadsheet provided, that I might be able to track down if you'd like.
It seems to me that if you were to encounter muliple soil layers of multiple resistances, a single proctor/nuke test may be impractical given the 5 meter range of the DCP. On the other hand, I don't think more information is ever a bad thing. I don't know if the forum would agree, but for shallow consolidated sediments, I just use a 1/2" probe rod, which speaks for over 10,000 PCF of bearing, and has basically the same depth-range of a nuke.
Let me know if you'd like the reference. I just changed companies, but I'm sure I could still get in contact with the PE we subcontracted for the work.
RE: Reliability of Nuk Density Testing in Exploration Test Pits
RE: Reliability of Nuk Density Testing in Exploration Test Pits
RE: Reliability of Nuk Density Testing in Exploration Test Pits
RE: Reliability of Nuk Density Testing in Exploration Test Pits
RE: Reliability of Nuk Density Testing in Exploration Test Pits
Glad to help. I do geotchnical/constructability services and seminars for a living, and don't usually give this advice away.