ASTM D2488

[rockiologist]

Can you identify a soil from a picture by ASTM D 2488? And if so where does it state it in the Spec. I have tried looking for it and can not seem to find any.

 

[fattdad]

No, a photo won't do. It's a visual-manual method!

f-d

¡papá gordo ain’t no madre flaca!

 

[msucog]

i think this says a lot

"1.6 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word "Standard" in the title of this document means only that the document has been approved through the ASTM consensus process."

for me personally, a picture might give me a clue as to the specific geology and then i may be able to conclude "yep, that looks like _________ which is predominantly an ML". that should be backed up with some sort of analysis and/or testing. also, local knowledge may be what the engineer is relying...again, such an assumption should be confirmed before you get off neck deep in the design.

 

[fattdad]

While I do not disagree with msucog, the D-2488 provides a method for an individual to classify soils based soley on visual characteristics and feel. If applied consistently by a single individual, you will get results that can be correlated from one boring to the next and identify layering distinctions in a boring. This is the true job of a field geologist, to be consistent. For that purpose and only that purpose, you can use it without testing or further corroboration - after all does it really matter whether you call a fat clay slippery gray mud or a sandy silt easy-to-crack clay, as long as you're consistent?

To convert the field information to universally accepted vernacular, I would agree the field geologist (or geotechnical engineer) should assign representative samples for classification via D-2487. Then it's just a simple matter of converting all of the slippery gray mud descriptions to fat clay and all the easy to crack clays to sandy silt.

f-d

¡papá gordo ain’t no madre flaca!

 

[rockiologist]

Tank you for your help mscuoq and fatdad. I should have clarified things. that samples had been previously described in the field. Because of the way the work plan was written the engineer insisted that all soils be identified by ASTM D2488. So we used the photos as another tool in helping ID samples for revision. We sent some samples out for testing according to ASTM 2487. 90% of the samples ID intial and revised were confirmed with laboratory data and approx. 5% had minor issues. Thanks again.

There is an old saying "When you take 50 geologist out to a site you get 51 different interpretations."