Strip Load surcharge on Sheet pile wall with sloped backfill 1

[lunera]

I am doing analysis on a sheet pile headwall for a CMP culvert under a railroad. I have been looking but have been able to figure out how to determine the lateral pressure from a strip load surcharge when the backfill has a 1:2 slope. I orginally just used the Bousinesq formula, but because of the slope and distance from the centerline of track, it seems that this may be much too conservative.

I was looking at this thread thread255-150849 , the last post mentions a reference from Poland, and I really wish I knew the exact source so that I could include it in my calculations, at least for why the surcharge won't need to be included. Does anybody know of a publication that refers to how to calculate the "Clear distance to surcharge"?

 

[Lion06]

The Bousinesq formula should work. Because of superposition, it shouldn't matter if the backfill is flat or sloped. I would use the Bousinesq formula. What is your condition that you think it is being too conservative? I recently verified some program outputs for this and thought that the lateral pressures were remarkably small.

 

[lunera]

The wall is about 23 feet from the centerline of the track, and by following the very last post in the before mentioned thread (thread255-150849: Surcharge Pressure on Retaining Walls) I calculated that the surcharge clear distance is 20.6 feet, which would then mean that I could disregard the effect of the surcharge. (18.1feet=height of surcharge material, 11feet=height of cantilever wall, 34 degrees = soil angle of repose). Although, not having the actual publication, I wouldn't be able to use this method.

What do you think? Do you agree with not considering the surcharge after a certain distance from the load?

 

[kslee1000]

That response was provided by forum member "miecz". Why don't you go to the forum administer asking permision to contact him directly. I believe he would be glad to help.

 

[Lion06]

I do, but I'm not sure where I would draw the line. I don't think it is necessarily outside the rankine zone. If you draw it out, it can be outside the rankine zone at grade, but be in the rankine zone at locations below grade. I would account for it to be safe. Based on your dimensions it should have little impact.
Poisson's ratio is more of a player than the actual surcharge magnitude itself.

 

[civilperson]

1:2 slope is damn steep and probably unstable, maybe you mean 2:1? (horizontal distance: vertical distance)

 

[lunera]

Yes, you are correct, it should be 2:1, thanks for pointing that out. Although I do not understand why slopes are referred to in that way, its seems that intuitively it would be rise:run, but the standard practice is run:rise?

 

[kslee1000]

lunera:

V:H & H:V both in use. There is no problem to distinguish the correct from sketch (unless you left out the symbol and numerical values for slope), when writing, try 2H:1V, or 1V:2H for clarity. Make sense?

 

[miecz]

lunera

Sorry, I don't have the name of the publication. I xeroxed these sheets 25 years ago from a book I couldn't purchase. The book was brought here (US) from Poland by an engineer that I worked with. Didn't occur to me to write down the name of the book (duh). I've never seen solutions like these anywhere else. For more discussion, and the derivation to the formulas posted in the other thread, see thread507-240214. Also, Here's a PDF of the solution to a surcharge at the top of a sloped fill, case No. 10.

 

[miecz]

Oops, got a call in the middle of the last post and forgot to attach the PDF. Here it is.