Design Compression of Soil

[CeaserMech]

I am working on an engineering design which includes underground piping.

We're having the contractor dig a 4' trench, fill 6" deep sand, then verify it is at a certain compression value.

Then they lay the pipes and surround the pipes with sand and again verify their compression value.

Finally they fill with Native soil to the top of the trench and again verify the compression value.

The goal is to make sure that over time (with rain and walking) the trench wont sink down.

Where can I find out good compression values to use for the sand and soil?

 

[jgailla]

You should probably look at ASTM D1557, the Modified Proctor test, to get an index value for the testing.
Underground piping outside buildings is usually specified as X% (usually between 90% and 98%) of the theoretical maximum dry density as defined by the Modified Proctor test.
The compaction in the field is typically measured using a nuke gauge, ASTM D2922.
You can get some good practices for buried piping from AWWA M23, which is about the design and construction of buried PVC pipe.
These are all American standards. There should be similar in European standards.

 

[CeaserMech]

Thank you so much, I will review the standards you mentioned!