Effect of Lateral Load form Emankment to Pile foundation 1

[lamy2781]

Hello Everybody,

I am working on a Highways Project which inculding Embankment. As the ground contain thick clay and the embankment are high, part of embankment are decided to constructed with piled foundation. And this raise the question......

For those embankment with no piled foundation, the embankment load will tranfer to soil and thus create the lateral load to the piled foundation next to it. However, I have no idea how to calculate for the effect of those lateral to the piles.

Here is some information of the foundation
The piled foundation is in 2m spacing with 0.35m square driven pile. Clay layers from various 15m to 25m.

I hope if anyone of you have such experience could give me some advices or give me some refrence to read.

Thanks!!!!!!!!

 

[jdonville]

lamy,

You'll need to provide additional information regarding the generalized soil profile, why piling will be used, what the embankment will be supporting, adjacent structures (if any).

Jeff

 

[Touma59]

I second jeff on the required info. If the soil is being retained by a retaining wall which in turn is supported by piles, then I'd suggest you calculate the lateral pressure produced on the back of the wall (including any potential surcharges) and apply this lateral charge at the pile top (+ any moment if any) then proceed to analyze the piles. For the laterally loaded piles analysis there are plenty of publications: Bowles, Das, Thomlinson, Reese & Van Impe, etc...

Tsoft;

http://www.tsoftonline.com

 

[MSEMan]

Are the clays over consolidated or alluvial?

I'm not sure where you are but I was involved in a project in UK (M5 JN 18-19 Avonmouth Bridge Widening) a number of years ago where we supported the wdiened portion of the existing embankment on CFA piles through peat and alluvial clay. One problem that we had was that the magnitude of the horizontal strain in the clay, at depth, was very large. As the piles were primarlily for settlement, we decided that we could allow plastic hinges to develop within the pile.

If the clays are soft, you may also have a problem want with settlement in cross section, both time related and absolute. The center of the embankment may settle more than the shoulders. When we did this excercise, we found a big problem between the hard shoulder and the middle lane.

If you want more info I'd be happy to provide additional detail.

 

[BigH]

As a first step you can check out horizontal induced stresses due to the embankment in order to determine the lateral loads on the piles. Horizontal strains can also be determined. Once the stresses are determined you can apply the loadings to the piles (and probably should check out the "pile block" as well. See Poulos and Davis' book "Elastic Solutions for Soil and Rock Mechanics".

 

[fattdad]

I would agree that the whole picture is not presented and quite literally a diagram would be nice. I also wonder if this is a "global" stability question, best solved by looking at the rotational failure surface (or wedge as the case may be) and then determining what forces are acting to drive the failure surface. If the piles are being used to retain the driving forces, you would then determine what restraint would be needed to give you a favorable safety factor and then attribute the need for additional restraint to the lateral loading on the piles.

Then again, maybe I don't quite "see" the problem as it is. . . .

f-d

¡papá gordo ain’t no madre flaca!

 

[BigH]

Ran across this site - you might want to check it out. Seems like it might be right up your alley.

http://www.ce.jhu.edu/rajah/My Web Page/NSF Workshop 2005/Kesavan/m003-web.ppt

 

[lamy2781]

Thanks all of yours kindly reply. And yours kindly remind me that I am not provided enough information.

May I give more information and hope that you can help me to solve or give me some related information that I can read by myself.

the information are as follow:

http://i145.photobucket.com/albums/r239/lamyuwang/engtipsQuestion.jpg

The site have granular Made ground at the surface and clay underneath.

Clay layer in the site is alluviual caly, which is normally to slightly overcondsolidated, may be simply say it as OCR = 1.

And alluvial sand and Galacial Till are underneath the clay.

I had read some information in the internet, and the lateral force acting on the pile are due to the plastic flow of soft clay and a drag force is created.

However, seems not many of them tell how to calculating it.

Actually, I am following "TRL Contractor Report 196" for the design, but it seems to me that this report is too complicated and also the charts are follow the experiment, may not shuitable for other cases.

So, I could like to see weather any of you have such experience and can share your design methodology to me.

Thanks a lot

 

[jdonville]

lamy,

The phenomenon is known as "lateral squeeze".

This topic is discussed in the FHWA piling manual V1 (1997) available here:

http://www.fhwa.dot.gov/engineering/geotech/library_listing.cfm

Another reference is here:

http://ecow.engr.wisc.edu/cgi-bin/g...tionsandreinforcedembankmentsonsoftground.pdf

Jeff

 

[lamy2781]

Jeff,

Thanks for your information. The FHWA paper give a estimation on the displacement.

However, there is no calculation on bending moment involved..... and the displacement is only rule of thurm as well

But anyway, thank you very much.