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Must dig, but solely by hand?

 
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Just looking for ideas, maybe.

I'm adding on to our little cabin, digging into the hillside. I did this already for a cellar, and so far that seems to have gone well. Our soil is clay. I get the soil wet and then dig away. It works.

It's just me digging this by hand, and it's time consuming (obviously). Any miracle devices for digging that I am not aware of (and don't say 'a team of people')? There's no getting an excavator back there, since it's only a narrow walking path (and steep, somewhat). I have used one of those auger drills, and they're OK...

If I found a tiny excavator, would it be worth it, in your opinion?

 
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Hi Stephen,

Yes, there are "micro excavators," and for the professional and a paying job they are worth the effort (sometimes.) However, most of the time, a five gallon bucket is the best bet. I would suggest digging "dry" as you are only adding weight by adding water. Yes it is hard but will be less effort to moving wet clay soil (I know from experience.)

As for a trick, yes there is one of those also, its called "a really good shop vacuum." These (if the earth is somewhat dry) can really make thing much easier on the back (until you have to empty the vacuum.) This is the method of digging in "confined space" applications.

Regards,

j
 
pollinator
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Location: Victoria British Columbia-Canada
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A few don'ts. Don't use a shovel that gums up. Don't work with a heavy bar unless there are large rocks. Don't use heavy tools where light ones will do. Never dampen clay.

Use the right tools to do it dry. On tough clay, that is already damp, you want to slice through it, not mush it up and have it stick to the shovel. Use a square spade that doesn't have sides. Sharpen the tool. On hard dry clay, use the lightest pick that will do the job. When working a face, place a bucket under your work so a good portion falls in. This saves a step. Clean up as you go. Don't walk on materials that are loose. Clay will pack and require more clean up energy if you walk on it.

The biggest energy saver is this. Determine the spot where it will be easiest to get to your maximum depth. Concentrate on getting there . Now you can stand on a flat surface and hack materials down. A scoop shovel makes floor clean up easy. I like to do deep stuff in a series of level shelves. Don't spend all day standing on a slope. A man in good shape should move a few tons per day when it's done right.

When clawing a face to a floor area, I like to lay a half sheet of plywood flat on the floor so that any materials that miss the buckets is easy to clean up. This is doubly important if the clay is rocky. Chunks of rock protruding from the clean up floor can stop the shovel dead. This is hard on the body, tools and production. The shovel slides effortlessly along smooth plywood. Never use a round mouth shovel for this since it wastes energy.

I did about 3 tons of backfilling today during a 90 minute run.
 
Stephen Lloyd
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Yes. Damp is key. Wet is impossible, and bone dry is slightly possible. But damp is great. The soil is heavier, but it also possible to make each shovelful really massive because it sticks together.

I just have a shovel. I don't know about shovels that don't gum up. You're saying that a sharp shovel doesn't gum up, correct? I'm trying to take your meaning there. Whenever possible, I use a pick. I love that thing. It's about a medium weight pick, and the end is not too curved, but more straight, which makes it possible to etch away at a slope very nicely.

I tried a digging bar, and that completely didn't do a thing for me. I had high hopes.

How is it that you can know how many tons you moved?

The good news is that I am now finished with digging (for now) and am on to the building part. Hooray!


Dale Hodgins wrote:A few don'ts. Don't use a shovel that gums up. Don't work with a heavy bar unless there are large rocks. Don't use heavy tools where light ones will do. Never dampen clay.

Use the right tools to do it dry. On tough clay, that is already damp, you want to slice through it, not mush it up and have it stick to the shovel. Use a square spade that doesn't have sides. Sharpen the tool. On hard dry clay, use the lightest pick that will do the job. When working a face, place a bucket under your work so a good portion falls in. This saves a step. Clean up as you go. Don't walk on materials that are loose. Clay will pack and require more clean up energy if you walk on it.

The biggest energy saver is this. Determine the spot where it will be easiest to get to your maximum depth. Concentrate on getting there . Now you can stand on a flat surface and hack materials down. A scoop shovel makes floor clean up easy. I like to do deep stuff in a series of level shelves. Don't spend all day standing on a slope. A man in good shape should move a few tons per day when it's done right.

When clawing a face to a floor area, I like to lay a half sheet of plywood flat on the floor so that any materials that miss the buckets is easy to clean up. This is doubly important if the clay is rocky. Chunks of rock protruding from the clean up floor can stop the shovel dead. This is hard on the body, tools and production. The shovel slides effortlessly along smooth plywood. Never use a round mouth shovel for this since it wastes energy.

I did about 3 tons of backfilling today during a 90 minute run.

 
Posts: 431
Location: Dawson Creek, BC, Canada
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Can I revive this thread?

It is the end of September.  Winter is not far away (I am at 56N).  I am replacing PT 4x4 deck posts packed in clay, with PT 6x6 packed in gravel.  I have 2 holes completed, where I dug out a 12 inch hole.  I am not happy with 12 inches, so my next holes are 14 inch.  Today, it started to drizzle.  I got one hole down to 46-47 inches, hoping for 48.  There was just enough extra water on the bottom of the clay hole, that my clamshell digger does nothing.  I can sink it into the surface 3 inches or so, I cannot extract anything.  This hole may be close enough to design depth for my purposes, but I have more holes to do.

In going from a 12 inch diameter hole to a 14 inch diameter, I have noticed that the extra room  allows me to "break"  the clay by tipping the clamshell handles side to side (or back and forth), so I can remove a chunk.  Except when I get close to 4 feet down, as the handles are now taking up the entire width of hole.

The soil is basically clay.  It is damp.

Oil patch is king up here to many people.  They like something they call "daylighting".  Use a high pressure sprayer and a vacuum to dig holes.  I don't like this, as I think the bottom of the hole is disturbed, and probably too wet.

But the idea in this thread where you use some kind of miniaturized bucket excavator to  work up a dry clay soil, and then use air pressure and air vacuum to lift the clay makes a lot of sense.  It won't disturb the bottom of the hole anywhere near as much as this "daylighting" I see up here.
 
Gordon Haverland
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Location: Dawson Creek, BC, Canada
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I'm apparently braindead too.  

Is there something I can pour onto the bottom of the clay hole, so that I can "bite" into this clay, to get it out?  I'm not crazy about having to buy sand to let me dig, but I want to get this finished before winter.  Sand is the only thing that comes to my mind.  If I pour sand in, it gets mixed with the clay that I dig up, and I'm left with clay-sand, which isn't something I think I want.  Maybe I can use it in the garden (it might be better than the straight clay I have).

Is there something "better" to add, to allow me to dig on these drizzle days?

Thanks.
 
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Location: Australia, New South Wales. Köppen: Cfa (Humid Subtropical), USDA: 10/11
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One of my Dad's drinking mates was a grave-digger back in the days before excavators, etc. He'd dig several graves a day. (Now that's bloody hard labour!)

Dad queried him how do you dig so many very large deep holes, in what is essentially all clay soil, with a spade and shovel?

The grave-digger took a swig of his beer, laughed, and said ... we only use spades to finish the hole so it's nice and even, we dig the hole with a FORK. Forks don't clump up with balls of clay like spades do.

Hope that information assists.
 
Gordon Haverland
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Location: Dawson Creek, BC, Canada
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Hmm, I don't see how to get a fork in there.  Maybe for bigger holes?

---

I ran across an older (1951) paper from Texas, on adding lime to clay soils to stabilize them for highways purposes.

https://library.ctr.utexas.edu/digitized/texasarchive/phase3/tx_MS990_1951.pdf

Just because something works for a civil engineering purpose, doesn't mean it would help in an agricultural setting.  The article seems to cover most of the bases.  And one of the improvements they (civil engineers) are looking for, is water transport through the soil.  So it may have some value.

They were looking at adding something on the order of 5% lime to the clay.

The effects they were seeing, were of a chemical nature.  (But, no mention of a control, such as using a very hard water (high in calcium) to mix with the clay.)  But lime is also a substance very good at absorbing carbon dioxide (probably not useful in this context) and water (which may be useful).

The hole I am currently fighting with, I can drive a bar into the clay maybe 2 inches, but the clay has enough water that its response is completely plastic.  There is no fracture.

I had gone out and bought an auger type post hole digger, but it doesn't want to dig any reasonable amount.  But, if I could dig a 6 inch wide hole down to (almost) 4 feet, I could probably expand that to my 14 inches quite easily.

I am beginning to think that any given method of digging in clay, has some range of soil moisture where it works best.  There are likely places where nothing works well.

But, many people are digging holes in clay by adding water and waiting a while.  This paper was looking at 24 hour time periods for the lime addition.  If a person can drive a bar 2 inches into the clay, adding about 0.1 inches of lime on top of the clay at the bottom of the hole, and then working the lime into the clay with a bar, adding some water (possibly hard water, high in calcium?) and then waiting a while (overnight), might allow you to more easily extract this next layer of clay.  Hopefully the addition of lime to clay which is mostly removed from the hole to be impounded elsewhere, would leave one with a clay that is better used for something else?

It would be much higher in pH than the original clay.  So perhaps one has to add elemental sulfur powder to the soil, to bring it back to a more neutral pH?
 
Gordon Haverland
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I think that there is an "optimum range of soil moistures" for any given person/tool/clay composition in terms of digging (by hand more so than with power tools).

The earlier hole I dug out this year, was too moist at the bottom, and hence the clay was very plastic.  The clamshell just squeezed clay into funny shapes, when I was (almost) 4 feet down.  But closer to the surface, this moist clay was easier to dig (only with a clamshell).  At no time dig using a bar seem to be useful in that hole.

My current hole, only 24 feet away, was considerably drier.  The clamshell would not drive into the surface at all.  The bar did little to break things up, it just made holes.  I went and bought an auger type post hole digger (a 6 inch auger might be useful for a 14 inch hole, it gives you a place to work out from (theoretically).  But it just dug a small hole with glazed sides, that never got deep enogh with respect to the rest of the hole to be useful.  A little time to let things further dry, and a drop of 10C in temperature allowed me to get this hole almost to 4 feet (after this break is done) using a trench shovel.  Drive it into the bottom, and twist with both hands to break a piece of clay off.  Seem to work better near the edges, if the shovel is perpendicular to the side wall of the hole.  But, a trenching shovel that is 3 foot 6 inches long starts running out of usability as the hole gets deeper than 3'6".

I think I found a newer version, but this computer isn't getting the same link, this seems to be a bit older.  But, this bulletin mentions that if enough lime is added to get the pH above 10.5, chemical changes to the clay will happen, in particular the clay will become a mixture of the cement phases CSH and CAH.

https://www.graymont.com/sites/default/files/pdf/tech_paper/lime_treated_soil_construction_manual.pdf

Not that we in agriculture are wanting to turn clay into concrete, but this does allow for better mobility for water in the soil.  When people in agriculture are adding lime, they are often adding limestone.  Unless you need the magnesium component, you are probably better looking for the calcium version of limestone.  But when civil engineering is talking about lime-treating of soils, they are talking about quicklime or lime slurry (or ...), not limestone.  At pH less than 10.5, the clay particles probably retain their identity, but the calcium ion will displace many of the other adsorbed ions on the particle.

If you are interested in the unusual jargon of cement chemistry, Wikipedia has a page on this.

https://en.wikipedia.org/wiki/Cement_chemist_notation

 
Gordon Haverland
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Greetings.  I am getting more experience in digging post holes in clay.

I am replacing rotten 4x4 posts, with bigger posts (most are 6x6, one was 6x12).  The remainder will be 6x6.  Digging a 12 inch hole is what I first tried, I don't think a 12 inch diameter hole is really enough for a 6x6.  Both of those holes at one time had a sonotube in them, to try and maintain the hole.  When I finally finished the holes, one hole was finished with a sonotube and one without.  The remaining holes are nominally 14 inch diameter.  I am packing the bottom 1 foot of the hole with 1.25 inch gravel, and packing the post in with 0.75 inch gravel.

I think every hole to be put into clay, should be approached with an open mind.  I think that by and large, they are all different.  And two holes adjacent to each other can be quite different.

There are a few kinds of clay.  By and large, clay particles are shaped like dinner plates, and they can stack.  Because of their disc like shape, they tend to have a much larger surface area per unit mass than spherical particles like sand.  Some clays have undergone substantial replacement of positive ions on the surface, and this can change the properties significantly.  In particular, there are clays with the surface positive ions are are replaced by sodium, which tend to have their own characteristics.

Some clays are known to swell (expand) when absorbing water.  I think Montmorillinite is this biggest culprit in this regard.    If the clays in your area do swell, I would say there is at least some Monmorilinite (sp?) in them.

By and large, clay soils will absorb water, and the water will take considerable time to go away.  This is probably in large part due to the high surface area to volume ratio of clays, and that clays tend to be wet by water.

Concrete is something people use with posts.  Concrete is a sponge (for water) which doesn't change its size.  Wood changes its size when the humidity of the wood changes.

The biggest problem for rot, is where wood is moist enough, and there is enough oxygen present. Mostly where water and air meet.   A 4x4 post in wet ground doesn't fail  at the bottom, there is much reduced oxygen there.  It fails closer to ground level, where the oxygen is present as well as the water.

----

Okay, we have a location for a (replacement) hole.  We use something (I use a mattock) to strip the sod off the ground in the vicinity of the hole, to a significantly larger diameter than the hole will be.  After the post is installed and packed in gravel, we want to build up  "wall" of clay on the outside edge of the hole at ground level, to keep surface water from running into the hole.  As this raises the level slightly, we want to add gravel as needed to keep the resulting profile flat or convex.  It may be that one can put a sealing layer on top, I haven't got there yet.

With our sod striped area being bigger than our hole, we want to mark out the periphery of the hole, and start the edges with some kind of shovel.  I am using a trenching shovel, it is narrow and curved.  I take 8 trench shovel placements to define the "circle" of the post at ground level.

Using that trenching shovel, I try to remove the top 2-3 inches of soil around the existing hole (nominally 3.5x3.5 for a 4x4 post).  Once I have a start to the overall hole, I go into hole digging mode.

If there is a pre-existing hole, that I am trying to enlarge; using an auger type hole digger can work.  I have had one hole, where the pre-existing hole was on the periphery of where the new hole would be, and do I never used the auger tool there.  I have had one hole, where the auger tool was basically useless.  If the auger digger works, what you are trying to do is enlarge a hole, for each level  you can "pilot a hole".  And it isn't necessary that the pilot is in the centre, just that it is somewhere in the hole plan.

By and large, my hole digging has been with a clamshell type digger.  A clamshell digger is reasonably good at shaping up a hole, where you are trying to remove a circular "shim" of material from the side.

If you are lucky enough to be digging an oval type hole (say to plant a 6x12 post), you prefer to orient your clamshell digger to work with the long axis of the hole.  You want to plunge the clamshell as deep as you can.  Unlike a shovel, there are no places for you to plant your feet.  You have to get your bodyweight on the handles in some way.  As I weigh quite a bit more than most people, I often can push down quite a ways.  If the clay is "plastic", to just  pull apart the two handles (to squeeze the clay a little in the hole) and you just pull up, you probably end up with some "nipple shaped thing on the bottom of the hole, and you might not have pulled up any clay.

Many plastic materials will fail in fatigue.  For the last hole I dug (today), the fatigue limit of the clay was about 10.  But, what I did was tilt my clamshell digger back and forth 10 or more times, to try and fracture the clay at the bottom of the clamshell.  And when I lift the clamshell up, I have a bunch of clay to remove.

The clamshell squeezes along a direction.  It may be that squeezing on a perpendicular direction on the same "plan" can help (with wetter clays).  If the clay is too wet, the fatigue limit will be large, and you probably won't fatigue the clay in any reasonable time.  As near as I can tell, at that point, you need to let the clay dry out some more.

It may be that other people have advice for digging holes in clay from the too dry side.  But this advice is mostly from the wet side of clay.

Good digging!
 
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