Joseph E.Bowles foundation analysis and design-swelling clay help 3

[22222222]

Hi all,

Looking for the help on one issue from this book in 5th edition.
on the page 392 there is an example how to estimate overburden Ps pressure to restrain expansion.

equation logPs=2.132+0.0208(76.6)+0.665(1.67)-0.0269(22.6)
=2.132+2.096=0.226kg/cm2


I do not understand how he got that result 0.226kg/cm2

I will really appreciate any help.

 

[PEinc]

Check the equation again. My 4th Edition, page 315, says:

logPs = 2.132 + 2.08Wl + 0.665Rhod - 2.69Wn (kg/cm^2)

You wrote 0.0208 instead of 2.08 and 2.69 instead of 0.0269.

 

[PEinc]

Sorry, I meant 0.0269 instead of 2.69.

 

[BigH]

I've got the 5th edition in front of me. The constant in front of LL is, as quoted in 5th edition, 0.0208 (page 392, example) and corresponds to the constant value in the equation 7.10 on page 391. Perhaps, if someone has access, they can confirm in the original paper:
Komorinik and David, JSMFD ASCE Vol. 95, SM1, pp 209-225.

NB. I have looked in my Foundation Engineering book by P.C. Varghese (Indian book), 2005. On page 388, section 21.4.5, they have the constant to be 2.08 and not 0.0208 as given in Bowles 5th edition. Apparently between the 4th and 5th edition, someone edited wrong and is causing the problem. (what I can't figure out is why the first term "2" has a line over it???)

 

[PEinc]

Well, I guess we can't ask Bowles about the line over the 2!

 

[22222222]

Hi all,

For BigH I want to say that the line over the 2.132 means maybe only that it comes from statistic evaluation of those 200 soil samples.

For PEinc
In 5th edition it is as I wrote before. I do not have 4th edition.
If you use this formula and the numbers as shown in book as in 4th edition, you will not get the answer 0.226kg/cm2, unless in 4th edition are different values for WL and WP in the example calculation.

logPs = 2.132 + 2.08Wl + 0.665Rhod - 2.69Wn (kg/cm^2)

I am now prone believe that the problem is maybe the number 2.132

Unfortunatelly I work now with swelling susceptible soils, so to know the answer would help a lot.

Anybody of your friends may have the original source?
Komorinik and David, JSMFD ASCE Vol. 95, SM1, pp 209-225.

Thanks again

P.S. In formula there is only unit of density as g/cm3.
Result of formula is in kg/cm2
I still can not fing that lost "cm"

 

[PEinc]

I didn't get the answer using the 4th edition either. Possibly there is a units conversion problem?

 

[BigH]

2222222 - your company should have the old equivalent to the now ASCE Geotechnical Journal! I've got them all back to 1975 (but in storage some 10,000 klicks away).

I, too, am baffled at Bowles example. One thing I noticed, though, and this is the discrepency in the 2.08 vs 0.0208 (and, in fact the 2.69 and 0.0269 as you would probably find the last term in Bowles 4th ed at 2.69) - in the 5th edition, Bowles modified the equation 7.10 so that the engineer could put in the liquid limit and water content as he normall sees them, i.e., 77 and 45. In the 4th edition (and in my Varghese book), the liquid limit and the water content are in the fractional form (i.e., 0.77 and 0.45). So, 2.08/100 = 0.0208.

I wouldn't worry about the lost cm - it is included in the derivation of the formula and the constants - how can you add a "percent" value for LL to a density, etc. - but it would be nice to see the whole of the derivation once so that you can put it to bed.

 

[22222222]

Hi BigH,

Seems to be that I will have to check that Komornik and David paper. I wish I could have had any library in my site. Just bears waking up after long winter season being not happy with the fact that we closed the access to the salmon main river pass.
As for the beer I will have one
Because not only clay are swelling. My head seems too.

 

[emmgjld]

I went digging in my father's old library (ASCE back to '61).
Komorinik and David, JSMFD ASCE Vol. 95, SM1, pp 209-225, 1969

log P = 2.132 + 0.0208[LL] + 0.000665[Soil Dry Den.] - 0.0269[% natural moisture]

P --swelling pressure k/square cm.
Soil Dry Den.--k/cubic meter

a small line is placed over the 2 in 2.132

The discussion is interesting. About 3 paragraphs down I read... "It should also be borne in mind that the predictive method outlined above is mainly intended to point out the regularity underlying the process-not to provide a formula for exact data, and that deviations should always be expected owing to the unknown influence of the structure."

Also note the potential limitations..."All useful test data from more than 200 disturbed and undisturbed clay samples form different soil laboratories in the country (Israel) were used for statistical analysis. The clay soils were tested for swelling pressure, dry density, natural moisture content, Atterberg Limits, percentage of clay, shrinkage limit and free swell. Indicative and classification tests were performed according to ASTM standards. Free swell and swelling pressure were tested according to the Bureau of Reclamation's suggested methods."

Also, selected from..."CONCLUSIONS
2. Almost no correlation was found between the swelling pressure and any of the above factors, individually.
4. Good coorelation was found between the free swell and the plasticity index irrespective of the chalk content.
5. Almost no correlation was found between the shrinkage limit on the one hand, and the plasticityindex or free swell on the other.

 

[22222222]

emmgjld,

Thanks for your time digging in the history. Good job!What I feel now is that the formula is useless bearing in mind that in the books we were talking about so far, there are either mistakes or the other authors did something what I do not understand.
Probably nobody has checked the original literature?
Now I feel that even there is some possible problem with the original formula.
From conclusion as you put here:
4. Good coorelation was found between the free swell and the plasticity index irrespective of the chalk content.

This is interesting but not even in the Bowles book there is an example or formula containing PI on the page 392, 5th edition. Just Wn,density and WL.

22222222