At Rest Lateral Earth Pressure Coefficient w/ Sloped Backfill

[EngSD]

I am trying to find some resources that discuss how to calculatate the at-rest lateral earth pressure coeffient when you have a sloped backfill. I have searched past threads and have only seen people's opinions without any resources (I would like to be able to point to something published in my calcs)

If it helps what I am trying to find is the pressure on the side of a pre-engineered building wall due to the building being loaded with corn.

Thanks

 

[Brad805]

I am not sure if you have a farm code in the US (assuming that is where you are), but the Canadian farm code provides recommended pressures for grain goods such as corn.

Brad

 

[MiketheEngineer]

I have seen such numbers - think from an AG University but seem to have a range based on corn type, moisture, etc.

 

[EngSD]

I really have all the information I need for the product to use in Rankin or Coulumbs forumlas (corn unit weight, friction angle, etc.) The problem I have is not being able to find anywhere where the problem of at-rest situation has sloping backfill.

Thanks,

 

[FixedEarth]

I use Ko = (1-sin (phi))(1 + sin(slope). So for phi = 30 Deg. and 2:1 backfill slope, I get 0.5 (1.448) = 0.724

 

[EngSD]

FixedEarth I had heard of this approach and it seems like it gives reasonable results. Do you know how this was derived or of a text that references this?

Thanks!

 

[FixedEarth]

Don't have a text or a reference. Could be derived from triginometric identities. I will let you know but don't hold your breath.

 

[DST148]

I have a manual which gives active components for retaining walls with sloped backfill and broken slope backfill. The reference quoted is Foundations and Earth Structures, NAVFAC DM-7.2. It may be a good source to look into for at rest conditions. Try if it's available online.

 

[RFreund]

Section 6.4 has of this article gives referance for the method FixedEarth has suggested:

http://www.cedd.gov.hk/eng/publications/geo/doc/eg1_chapter6.pdf

EIT

http://www.HowToEngineer.com

 

[FixedEarth]

Good work RF. Attached is the page you referred to. The publication is GeoGuide 1: GUIDE TO RETAINING WALL DESIGN, Geotechnical Control Office, Engineering Development Department, Hong Kong, July 1982.