Hi Daiane,
I bet you get periodic variograms ! I did a similar study with a US army type push penetrometer along transects, and have seen some off shore and barrage penetrometer variograms, they are all periodic (even though the measurements can hardly be considered to be the same scale).
Additivity isn't an issue really, as it is difficult really to distinguish between one golp + half a golp done sequentially and one large golp equivalent to 1.5 normal golps done in one hit. I hope I understand correctly your means of measurement ? If I remember rightly though as the depth increases the effect friction increases as the length of penetrometer touching the soil is greater ? You should perhaps correct for this effect prior to analysis, it may present itself as a trend which you could filter out, or you could use more physically based methods.
I shall hunt around for some references and send you a copy of the work I did for my degree. I don't think it was published widely but was presented at the "Journees de Geostatistique" , Fontainebleau, 1999 and some record may exist on their website.
cheers
Benjamin Warr
Research Associate
Centre for the Management of Environmental Resources (CMER)
INSEAD
Boulevard de Constance,
77305 Fontainebleau Cedex,
France
Tel: 33 (0)1 60 72 4456
Fax: 33 (0)1 60 74 55 64
e-mail: [EMAIL PROTECTED]
> -----Original Message-----
> From: daiane [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, June 28, 2001 4:29 PM
> To: Ai-Geostats
> Subject: AI-GEOSTATS: Aditivity SPT data
>
>
> Hello
> I have a database which consists in samples of SPT (Standard
> Penetration Test) surveys. This kind of survey is frequently used in
> the civil engineering to determine parameters of soil resistance. The
> samples and consistency values are collected each meter, being just
> integral values representing the number of golps needed to penetrate
> downwards 1 m thickness of soil. The residual soil of the area is
> originated from decomposed basalt.
> My doubt would be on the aditivity of the data for application in
> ordinary kriging and simulation geostatistics.
> I would like to know if is there some impediment for the
> geostatistical
> treatment for this type of information; would also appreciate
> bibliographical recommendations regarding the subject.
> Greetings
> Daiane
>
>
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