3" OD split spoon sampler 2

[Okiryu]

Have you ever used this sampler? It has 3-6" long sleeves inside that collect the sample. It has some corrections to make the N value equivalent to the standard 2" split spoon. In what type of soils do you use this 3" sampler? Can the samples collected in the sleeves be tested for direct or triaxial tests?

 

[Okiryu]

Also, Is this sampler typical/common in the US?

 

[oldestguy]

I did a search for Dames &Moore sampler and this is what came up. It may answer your question.

http://www.eng-tips.com/viewthread.cfm?qid=82930

 

[Okiryu]

As always, thanks OG. Very good reference.

 

[oldestguy]

I once interviewed for a first job with Dames & Moore. Wasn't hired, but it left me wondering how their design recommendations based on shear strength tests on those rings from the sampler could be interpreted to show what settlement was likely, since shear strength seldom governs the design.

 

[Okiryu]

OG, I guess you meant to say that settlement seldom governs the design.

We are using a 140 pounds hammer so we can switch to the standard split spoon sampler. Yeah, I have to do a literature review on how to use the data from the 3" sampler. I heard the Professor Sowers made some correlations for this sampler so I will check it. Thanks again.

 

[BigH]

Well, I've used three inch split spoons before - when in more gravelly soils than in sands and clays. Winterkorn and Fang (and Fang, later, the 2nd Ed) has a chart of such. Thought this was called the California sampler?

 

[Ron]

Okiryu.....As OG notes it is the Dames and Moore Sampler or also called the Modified California Sampler. Burmister developed correlations for non-standard samplers, comparing various diameters to the standard split spoon in ASTM D1586. Check ASTM D3550 for the larger sampler and search for Burmister's papers in the 1940's. Others have done similar correlations.

I'm not sure that Sowers did anything with the 3" dia. sampler. He did extensive work with the small, dynamic cone penetrometer, commonly referred to as the Sowers Penetrometer. This is a hand-held, DCP that is portable and has good correlation with SPT. I spent 18 years at Law Engineering when Sowers was there, so we were all familiar with the Sowers DCP amd I'm fairly sure each branch office had one! I've used it quite a few times over the years.

 

[Okiryu]

BigH, Ron, thanks for the replies. Yes, I think that this sampler is called modified California sampler. We are using it for offshore loose gravels. It has a removable catcher so samples can be retained. I think I have a copy of F & W book. I will take a look. Hope I can find the Burmister's papers also.

 

[oldestguy]

OKiryu: In reply to your comment, placing enough safety factor on a soil rupture failure might be the practice of some, but not me. The question on determining the settlement for granular soils may set some back in doing that computation, but in my experience settlement allowable governs the recommendation for soil bearing for most foundations on most soil types. Look up the ASCE Journal of Soil Mechanics and Foundations, paper number 2135 of SM 4 group by B.K. Hough labeled "Compressibility as the Basis for Soil Bering Value". That was in August 1959 and it had more discussions on the subject that any ASCE paper before it. Of course Peck and others got into the argument. Hough was my undergrad and grad soils engineering professor at Cornell and later I worked a few years for him in his private Prentice. In later work places and in private practice I used his methods and have passed them on to those I have worked with, with success, no failures. Hough's new term "Bearing Capacity Index" has worked out great for me. Where shear strength values are known, yes a safety factor is applied, but only RARELY governs the design recommendations. I've given this same "sermon" before on these rooms so a search on this WEB site may bring up more details for those interested. The second edition of Hough's text (Basic Soil Engineering)is sufficient to get one going on how to use it on a spreadsheet. Some improvement modifications of the original paper methods are needed then.

 

[Okiryu]

OG, yes agree. I reread my previous post and noted that I made a mistake. I meant to say that settlement NORMALLY governs the design. Also, I have the Hough's charts you mentioned (I downloaded them from your old posts), but I was wondering if you can share that paper with us. It will be interesting to see the discussions. Thanks!

 

[oldestguy]

OG back with a little info. The original paper had some approximations on using things not useful now, but here are three jpg files. The first is one page of the paper showing the reasoning for the new factor, bearing capacity index. Third a page showing relating that factor to blow count (the old rope on the cat head result). Secnd a copy of a page from the first edition of Hough text and my notes where some of my test data fits and the value "C" for the various lines plotted near the right border. Note that some f my plots have less slope than Hough's figure had.

 

[oldestguy]

OG again. For using the Hough method in a spreadsheet you do the computations for small layers at a time, such as one foot thick each and add the results. Then, if you wish to get fancy and design footing foundations for equal settlement, run a whole batch of computations varying column loads and footing size, plotting that with data points labeled for settlement computed. Draw lines of equal settlement. Then give to structural engineer to pick his footing size for each column load, hopefully coming close to them actually setting equally.

 

[fattdad]

35 years ago in Seattle, we'd see the D&M sampler quite often. Good in till as the diameter would allow for better sample retention. Quite a bear to re-clean though!

We always used a 300-pound, downhole, "Jar" hammer. We always used mud-rotary.

Wasn't an engineer at that time. Now, I'd wonder about sample disturbance effects on Su or 1D testing.

We just don't see these in Virginia.

f-d

ípapß gordo ainÆt no madre flaca!