SPT blow count 1

atasidas · Jun 10, 2002

Hello,

I have a question regarding nonstandard and standard procedures of SPT. How do we convert the SPT blow counts or standardize if they have been performed in a nonstandard way say with 300 lb hammer and 18 in fall with a 3 in spoon instead of 140 lb hammer and 30 in fall with a 2 in spoon?

Please help.

Thanks
Atasi

Sean2 · Jun 14, 2002

I am not aware of any such correlation. However, if you can fund the research, and wait at least ten years for the research to be completed, you may have an indicative answer.

The SPT is strictly only a comparative test, and should really only be applied to a sand. However, it has been found to provide useable information in slightly finer and slightly coarser material, and has therefore been widely used.

In order to use equipment which differs significantly from the standard equipment, you need to confine its use to comparative testing. In other words, you can compare blow-counts in different materials on a given site, but you can't use the test to measure material properties unless you have established the correlation in advance. This has been done for the SPT.

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SPT blow count 1

atasidas

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