Pipe Zone Material

[martin888888]

We have a 24" coated steel pipeline that we need to be careful with the pipe zone material as not to damage the coating. The pipeline also carries a highly explosive type of gas. We specified out 1/4"-minus granular material within the pipe zone. Contractor is asking if they could put dirt or mud in the pipe zone and then 3/4"-minus above that. Anyone have experience with just native soil in the pipe zone?

 

[civilperson]

If the design optimum moisture is held in the native soil and the compaction of the bedding/spring line is uniform and meets compaction requirements then the pipe will utilize the available wall strength. The backfill is equally important with thin lifts compacted at optimum moisture content until a few diameters above the pipe.

 

[BigInch]

Generally it should be finer materials, sand prefered, within 12" of the pipe. Some smaller diameter gravel content is acceptable, if it is round, with no sharp points or edges. Native material is generally OK, if it meets the small diameter, no sharp edge criteria. Optimum compaction water content is OK, but excessive water must not be allowed in any material, especially plastic clays as voids may be created upon drying.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[dicksewerrat]

Controlled density fill to cover the pipe.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com