Limitation of CPT wrt soil type

[ashjun]

Hi,
Could anyone guide me on any published literature on the use of cpt in certain type of soils.

This question may be trivial to most of you; but any reference may be helpful.

Regards

 

[BigH]

As given in Donald P. Conduto’s book Geotechnical Engineering, Principles and Practices (1999, Prentice-Hall), Table 3.5, the cone penetration test is suitable for all soils other than gravels (and, by inference those materials larger than gravel sized). The table, developed fromJames K Mitchell (1978) “In-Situ Techniques for Site Characterization,” Site Characterization and Exploration, pp. 107-129, C.H. Dowding, Ed., ASCE, gives the following suitable soils for in-situ testing:

Standard Penetration Test: All except gravels
Cone Penetration Test: All except gravels
Pressuremeter Test: All
Dilatometer Test: All except gravels
Becker Penetration Test: Sands through boulders

As expected, most in-situ testing has troubles with coarse sizes (gravels and above). The notable exception is testing done by the Becker Hammer (developed in Canada).

Hope that this helps.

 

[ashjun]

Thanks BigH!..you are an angel!
I will go though the references and update on this. I was more interested in sand gravel mixes; performance of CPTs in sands with different gravel compositions.
I hope someone has come across such literature.

Regards

 

[Focht3]

If there is, it won't be much. Since sand/gravel mixtures have fairly high densities and bearing capacities, most (all?) conventional CPT rigs can't get a lot of penetration into these soils. The last time I looked, Fugro's fully enclosed truck rigs max out at about 60 U.S. tons. Hogentogler's may be higher, but not by a whole lot. That seems like a lot of force, until you think about the total sleeve friction. The load isn't all transferred to the CPT point -



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