GLASS JARS or PLASTIC BAGS? 1

[boringman]

Hey guys! So I need a little help convincing my office to switch from plastic bags to glass jars for SPT soil collecting. We're currently using plastic bags and storing them in a big burlap bag (potato sack). We usually collect the entire split spoon. Does this seem crazy? Or maybe I was spoiled at my last company.

1)Do you use glass jars or plastic bags?

Glass Jars:
a) they keep you organized (easy to store, easy to access, easy to ship)
b) they can be lighter (depending on how much sample is taken from plastic bags)
c) air right --- seals in moisture
d) more expensive, but not when compared to the cost of drilling

Plastic bags:
a) doesn't really encourage post-review
b) disorganized, if you want to look at a sample you have to puzzle through the bag/box
c) don’t completely close (unless it’s ziplock)

2) Generally, how much sample is necessary for collection (from a standard SPT split-spoon sampler)? I feel like a small 4-5” representative sample works?

 

[geomane]

We use plastic jars. My last company used plastic bags. Whirl pak bags are better than ziplock bags. I like the jars better, but they take up more room and are more expensive.

As far as sample collection. You need a sample from every soil stratum. The whole split spoon sample would be better than the bottom 4-5”, if there were any material changes within that sample depth. It really depends on who you have logging the borings and if you can trust them. If you don’t have an engineer or geologist in the field, I would want to see the whole split spoon sample.

 

[oldestguy]

While I've always been with the glass jar method, I have wondered how many of those saved samples ever gets looked at again. The last I was involved with them we kept them for 90 days and then dumped the sample, washed and reused the jars. In my practice all jars were tall olive jars so as to provide a sample for Qu test. Lids were thrown because boring no. sample no, etc. were scratched on the lids. For the thousandth of samples so handled and stored not one was ever needed for a court case. On very very rare occasion a sample not previously tested with penetrometer or Qu test, it was the tested to add to the data. In summary, I'd say either way is OK and be prepared to dump them soon after the job is done and report well on its way..

 

[MTNClimber]

I would recommend trying to not overthink it. Both works. I would rather have jars for organization but I’m not too lazy to take the 5 minutes to line up samples on a work bench either.

Jars aren’t always air tight though. I’ve found old samples of peat that lost most of their moisture.

 

[Ron]

In the company I grew up in, glass jars were the norm. When I started my own firm many years ago, I used glass jars until I could no longer get them. Switched to plastic bags. Decided that moisture content would degrade so we started doing moisture content quickly while maintaining the rest of the sample...pain in the a$$. Glass jars are better for many reasons.


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[GeoEnvGuy]

Ziploc freezer plastic bags, when sealing the bag the majority of the air should be pressed out. Each borehole gets a larger plastic bag or bucket which is then laid out and reviewed in the office or lab.

The minimum amount bagged would be the minimum identified to complete the lab testing. In practise we typically recover the whole representative SPT sample recovered.

 

[fattdad]

Our state DOT requires glass jars. For the case that there is a change within the SPT, we'd also require both soils be retained in separate jars.

Prior to my current job, I was in consulting. In that instance, I also only saw glass jars.

I'm unwilling to revert back to plastic bags, which I haven't seen in use EVER in Virginia. Used to see them when I was a field geologist out west.

f-d

ípapß gordo ainÆt no madre flaca!

 

[MTNClimber]

It’s definitely a western thing.

OP, I’m going to guess that your a younger engineer at a new(ish) job. I’ve learned the hard way to choose your battles carefully. If this is your only criticism of the company then I wouldn’t worry about too much about what I’m going to say. However if this is your first of many issues with the way the company does things, then hear me out.

The first job I took after moving west, after spending close to a decade working in the northeast, came with some culture shock. The company I worked for had a very relaxed way of viewing....just about everything. The amount of design work was pretty much nil as they pretty much just pumped out reports, although they told me otherwise in my interview (this is a common theme in Colorado). Most of their recommendations were “based on experience” without any theoretical or empirical data. I naturally questioned things and it really rubbed people the wrong way. But having questions answered with “that’s how we always do it” and not any sound reasoning is just lazy in my book. I decided that I was going to put in my time to “repay” them for getting me out west and leave. But by the end I had a huge target on my back. To the point where I’d get 6 reports to write on my desk all at once, with similar short turnaround times. I questioned them on how they used their samplers, store their samples, lack of staff training with sample classification and safety, fluid pressures, skin friction recommendations and so much more. They would literally extrude their Shelby samples, put plastic wrap around the sample, and store them horizontally in a not so temperature stable room. Although I didn’t care too much about the target on my back as I knew my time was limited there it was an eye opening experience. I wasn’t aggressive in my conversations, except for the safety issues since lives were literally at stake, and I was still met with a lot of resistance and viewed as a pain in the ass. All I was asking for was why they did it this way and not as recommended in the references I had or based on my experience back east.

Take what you want from my experience but if jars versus bags is something that is really affecting the quality of your work and it has to change, just know that even if you have 3 text references explaining why something is correct, people are hesitant to change, and apparently it can cause tension.

 

[oldestguy]

OG again. If trying to change for what ever reason and there is reluctance as MTN Climber brought up, why worry? Life is too short to get into arguments over nothing really that important. If quality of the output is affected, yes, but I doubt that it is. As an old duffer, the way we always did it sometimes has merit of sorts. You will be there some day hopefully.

 

[boringman]

Wow, wasnt expecting so much solid feedback! Thanks everbody. I wouldnt be able to get this insight anywhere else.

After long consideration, I think I'm going to take the advice of not bringing this up. I have a tendacy of "dreaming too big" and I dont think I fully understand how much of a headache this might cause for people. People like what they're use to. Plus, as mentioned, I dont want to bring any unwanted attention to myself.

Perhaps if I started with bags I'd be asking this the other way around.

Thanks again!

 

[MTNClimber]

So that company I worked for was awful. Every time I talked to one of my engineering friends back east about how the company operated, they would just be in shock.

But I’ve learned several things from the experience. The biggest is if your reputation, professional license, safety or safety of others are not on the line, ask yourself: Is this the hill I want to die on? I chose to fight many things because those items were on the line but decided not to fight other issues because they didn’t really affect me on a larger scale.

On the bright side, when you become in charge of the project budget, you can add a few extra bucks for the jars. Who knows, maybe you’ll start a trend at your company.

 

[BigH]

For what it is worth - I started out using glass jars and liked them. To one post, the project engineer (manager) in the company I was with would review every jar with the field engineer. This carried over with a company I joined after only a few years with the first (interestingly, all the principals of the first company used to work for the 2nd company). I used glass whenever possible but there were times, like in the Northwest Territories that you lived with whatever you could get your hands on - usually plastic bags.

One other point - I always put the hole sample into the sample container however, removing obviously granular "wash" - yes, many of our jobs used wash boring techniques. Whenever I had two types of material in the spoon, I separately put them into separate containers - when using bags, then both bags would be put into a bigger bag. Early on I had a job where there were "layers" of silt to clayey silt (only a few mm thick) and there were a few samples that were divided into four separate containers.

 

[TDAA]

I started off with glass, but now use bags, as I also moved to the west and use mostly Modified California barrels.

I find MTNClimber's assessment of Colorado bit odd, as engineering is based on learning from past experience, and that of others. That is how engineering started, with people learning from mistakes and successes. Not everything needs to be calculated out as a research project, and various , streamlined methods are used throughout the world since experience shows them to be valid. Heck, many shortcut methods are taught in textbooks. I have had a good experience in my move, learning what is done locally, as the practice is different based on what the earth gives you to work with.

So to counter his point, as a manager, I would welcome discussion on any proposed change, as long as you have a valid reason. If the reason for you to ask is why do we do it this way vs. another, that is valid enough in my book. It shows you want to learn (even of mundane details such as sample containers). Just be ready to hear what the answer is and provide sound reasoning if you want to change the way it is done. If you get resistance, don't take it personally, and learn to let it go. If the response is "this is the way we have always done it, and we have not had issues with it", then there will likely need to be a good reason to change the status quo. "That's not what I'm used to" is not really a good reason for everyone else to change their mind - you might need to adapt.

 

[MTNClimber]

Not to derail this conversation but it seems like the OP got what they wanted from this thread so I'll respond to TDAA.

TDAA - I'm glad you got what you wanted from Colorado. I personally didn't and I'm sure it had a lot to do with the people I have interacted with. But if I asked you why you use this skin friction value for a certain material and you say "Because that's what we always use." I'd ask if you can you provide me with pile load test data or a reference with guidelines? "We don't do load tests. We actually don't hear about load tests being performed often." Why are these values different from the values other companies use in their reports? "Not sure." Ok, so is my stamp in jeopardy for recommending these values in my reports? "We don't get pulled into lawsuits too often." ...That's comforting. Are we being too conservative and wasting the client's money? "I don't think so."

I realize engineering is heavily based on past experience and results but we have now advanced past throwing darts at a board on a lot of topics. Especially when it comes to skin friction values. You can't ever run a load test? Come on.

Like I said, there's a good chance that it is the people that I've interacted with. But the thing that always got me was that my employer back east would always have a competent person that could sit down with you and explain things in a clear and concise way that is consistent with the practice used in the area.

I've talked to multiple people originally from the northeast about it. I know that I was not alone in feeling that there are more instances of inadequate engineering and construction practices. I'm 100% sure that there are plenty of great and intelligent engineers and geologists in Colorado, I just haven't gotten the chance to work with them.

I could go on a multi-page rant about my experience but I wont. Instead I just plan on going back east in a few months to regain my professional sanity.... right after ski season is over.

 

[BigH]

MTNClimber - in the companies I worked with in Canada a long time ago - every report I wrote was thoroughly reviewed by a more senior engineer and, after his review, by our Chief Engineer (who happened to be a student of Terzaghi and is still, at 91, practicing although in advisory type roles. It is always best to have more "wise" people reviewing reports.