Infiltration Bed Compaction

[cieg22]

I'm designing an infiltration bed for a residence. It includes AASHTO #3 stone and HDPE pipes and fiberglass catch basins. I've noticed that the pipe and catch basin manufacturers require that backfill around their products be compacted in accordance with ASTM D2321 (the standard for gravity-flow pipes). However, the DEP spec requires that the crushed stone in the bed be loosely compacted.

I know infiltration beds with stone and pipes are common. Can someone please explain what I'm missing, or how this dilemma is addressed?

I don't have a copy of 2321 handy. Does anyone know if it addresses loose compaction for infiltration?

Thanks, everyone for your time and help!

 

[civilperson]

Start compaction a foot above the top of pipe and use 85% of Standard proctor to assure no ditch settlement. Use higher compaction under pavement.

 

[cvg]

this type of gravel is difficult to test the compaction using proctor methods. relative density method is more appropriate for gravel or sand drainage beds. However, for a residential application, I would specify a minimum of compaction and consider whether you want to require compaction testing at all.

D4253-93
Standard Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory Table

D4254-91
Standard Test Method for Minimum Index Density and Unit Weight of Soils and Calculation of Relative Density

 

[cieg22]

Thank you both for your time and help!

How would these options mesh with the manufacturer's spec to backfill and compact in accordance with D2321?
I'm afraid of getting into a situation where the warranties on the pipe and catch basins are voided because we specicied something other than what the manufacturer requires.

 

[cvg]

if you aren't in an area with traffic or other heavy loadings, what do you think will happen to your pipes or basin to require warranty service? At worst, you will get some differential settlement. make sure you have plenty of slope on your pipes to maintain gravity flow. Additionally, this type of gravel with just a small amount of compactive effort will remain very stable and settlement should not be a big issue. Why don't you contact the manufacturer and ask them for a recommendation?

 

[cieg22]

Thanks, CVG. I did contact the manufacturer, but didn't get very far. It just bothers me that there seems to be a contradiction between what the manuf and the DEP specify.