Dynamic Cone Penetrometer, 45º vs 60º and hammer pounds

[lawcus]

HI Experts,

We have a DCP from Humboldt that has a 45º cone point and 15lb hammer.

All the other references I see is using a 60º cone point with a 17.6 lb hammer.

I am guessing the results will be different. There are a lot of correlation tables for the 60º cone DCP while for the 45º DCP from Humboldt, we only have 1 from ASTM STP 399.

Is there other reference that I can use for the 45º cone point and 15lb hammer?
By the way I need a DCP to UCS estimate correlation. I have a DCP to N value:

But I am not entirely sure if the N-value here can be used for correlation to UCS.

Can anyone help me?

Cheers

 

[EireChch]

What are you using the UCS for? foundation design ? Is your hand being forced that you have to use DCP data or is there alternatives available?

I dont really like using DCP, the only time we use it is for small residential housing jobs. With a bit of conservatism it is probably ok. But Short answer for me, i wouldnt use a correlation from DCP to N to UCS. Too many correlations IMO.

 

[Ron]

What you have is known as the Sowers Dynamic Cone Penetrometer. It is correlated to SPT. There are numerous references to this.

Here is a link to an article with other correlations ASCE