references for use of a t-probe?

[dirtsqueezer]

Does anybody know if there been any papers or studies done involving a t-probe (long metal rod with a handle)? I wanted to find some definitive documentation on penetration depths, and couldn't find any literature on the web. It seems obvious that applying the weight of your body a point load would help determine the strength strength of a soil. Any ideas?

 

[jocrow]

Although applying your body weight to a t probe will effect a point load the result will be qualitative and only of limited use, mainly to yourself, relative to how hard you pushed down during other tests. This test can not to my knowledge be uniform enough to give sufficient soil strength data.

For quantitative results it would be preferable to use a 'mac' probe or similar where you have a known weight falling vertically a known drop height and the penetration is measured and resistance/relative density calculated. See BS5930:1999, BS1377-9:1990 or ISSMFE(53)

Good luck

 

[coneboy]

Greetings Dirtsqueezer.

I commonly use a "T" probe for a rough estimate of the compaction. The T probes that my co-workers and I use are simply pushed in by hand until refusal is met. We stricly use it for spot checking backfill procdures. Typically I can not push probe in more than one to two inches if compaction requirements are being met. If the soil has softened or is loose then I will be able to push the probe all the way. Regardless of how far the probe penetrates I will still have a technician do a density test (nuclear, ballon or sand cone) as the probe is only a very general indication of density. Unless there is more advanced probe than the one I use I would only use this procedure for rough spot checks of the soil.

Hope this helps
Coneboy

 

[dirtsqueezer]

Well, it seems that responses here have answered my question with the response that there are no known quantitative studies associated with the t-probe. I have talked to engineers that say that the t-probe is limited for use with sand, and some inspectors that will use them in place of a nuclear densiometer for their testing. If I find out more, I'll post it here.