Density testing to 4 feet from grade?

[SteveNNY]

I am wondering if there are ASTM approved methods for measuring densities beyond the capabilities of a troxler or a penetrometer. I had thought there might be a penetrometer which could reach deep but it seems not.

I have to do deep box outs due to pumping am backfilling with sand. Trying to avoid the pump traveling through sucessive lifts using a three to four foot lift but need to prove density as the area will be a roadway.

Have tried geogrid / 4" stone / geogrid / 4" stone layers in nearby areas with poor results.

 

[jdonville]

SteveNNY,

You will likely not get your compaction with 3-4 foot lifts. You will need to bring up in at most 8-inch lifts (loose placement). To ameliorate pumping, you will likely need to use stone - sand may not be porous enough to allow trapped water out of the fine pumping soil.

Contact Tensar for advice on designing geogrid-reinforced subgrades.

Jeff


Jeffrey T. Donville, PE
TTL Associates, Inc.

http://www.ttlassoc.com

 

[fndn]

If the area is not too large you may consider a 2 sack of slurry mix, also called mud slab or flowable fill. It has more stiffness than compacted and dense soils, requires liitle labor and works if you have a limited area economically. If your roadway section is large consider this- Most of the pumping is caused by saturated soils and sometimes high perched or ground water conditions. In the past, I have used a trench that is about 2 feet lower than the repair section to draw any water away and then have placed 18" to 24" of 3-4" rock, followed by 12" lifts of compacted soils. Let us know what works for you.