Horizontal Subgrade Reaction in "Peat"

[claytill]

I was wondering if anyone has any experience estimating the horizontal subgrade reaction in "Peat"? The application is for a horizontal bend in a 42" pipeline (pressure unknown)that is ~2.5 m deep. We will likely be completing some field sampling to classify the peat. Also, any advice on specific field tests that would be relevant to determing the horizontal subgrade reaction would be appreciated.

 

[BigH]

What I would probably do is determine the "zone of passive resistance" that you will need. Dig out the peat for that size plus a bit more (offset 2 to 3 m at base and then go up the passive angle). Backfill with granular material (sand and gravel or coarse sand). Then the 'zone' which is stressed by the passive push is wholly within material that makes sense. Counting on any passive in peat doesn't make much sense. Just a thought.