Use of Proctors 1

[GODsRebel]

Is there a limit to the amount of field compaction tests for any given proctor?

 

[boffintech]

At the last company I was with a technician used 13 proctors for an entire job. These 13 proctors were generated from cuttings from the borings that were performed during the geotech exploration phase. Lots of so-called check points were "performed" during the course of the work; however, over 1 million yards of material was moved. I was surprised that no other senior technician, no supervisor, no project manager, or anyone else thought that 1 additional proctor might be needed on a 1 million yard earth moving job spread over a 50 acre project.

 

[looksatstars]

When you have different tech doing the proctors and field testing. How would they know which proctor to use for which soil type considering the proctor usually take a day to complete?
I know if the Maximum Dry density MDD are not close its easy to tell by your dry density and if the soil is different (ie clay till and sand) you can tell be moisture content MC). But if your soils are similar, it comes down to feel.
For complex jobs that use borepit material, it should have be test pitted and samples taken for sieves,proctors before hand.
I think this post shows how important experience is for the field testing as there is no right or wrong answer, everyone has good input.

 

[COEngineeer]

We all know most Geo tech companies hire HS graduate with 2 days of training. Very sad . I am glad I only tested side walk subgrade because I had no idea what I was doing . Nobody is going to die !

 

[fattdad]

sometimes it helps to look at real data:

http://home.comcast.net/~fatt-dad/proctor-summary.jpg

This is from a real job where followup dilatometer testing showed that the "compacted structural fill" had the consistency of "mud" As you can see from the FDT results, there was no control on moisture content and the reference proctor was chosen to provide (for the most part) 95 percent compaction. I'm not sure anybody ever considered the position of the ZAV as you can see several passing tests that are on the bad side of the ZAV.

f-d

 

[BigH]

Talk about no control - I am aware of soil borings done after placement of dam fill that, when taken, the fill was described as "sandy ice".

 

[boffintech]

COEngineeer wrote, “We all know most Geo tech companies hire HS graduate with 2 days of training. Very sad .”

Well whose fault is that? Chapter 17 of the IBC requires certain inspections for various structural elements of projects. The power to enforce the competence level of those performing the testing, observation, and reporting is in the hands of design professional of record. If you guys started rejecting some of the bullshit work produced by these idiots, some of whom are my coworkers, things would change. But if you get a number of nearly illiterate nonsensical reports from a job and don’t call the lab and say something like, “What IS this load of non-sense you are sending me?” then the sadness you refer to is never going to change.