I’m planing on putting in a driveway and would like to do the excavation myself. I need to dig about a foot of compacted clay out for a gravel bed. The driveway will be 10′ wide and about 100′ long. Is one of the Bobcat type machines with a front loader up to the job or should I rent a full size back hoe. I also want to move the spoil to another area of my yard for fill.
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The job's a little more complicated than appearances. First, clay in the ground is not considered structural. It will compact about 5% when properly dried and hit with a sheep's foot or vibratory roller. If you do not compact your driveway properly, it will settle and cause you problems. Some people get compaction by cutting the driveway out with a finish dozer, like a cat D5/D6, and spending enough time rolling on it for the weight of the dozer to compact it.
Drainage problems - make sure they're sorted out. In your shoes I would consider hiring a small outfit with a finish dozer to cut it out for you. The risk of settled/heaved surface is expensive. btw clay swells generally 10% when excavated and compacts generally 15% if you have a fill area on your drive.
remodeler
---"...spending enough time rolling on it for the weight of the dozer to compact it."---
I would not count on the weight of a dozer for compaction. The tracks spread the weight to nothing, like a few lbs/inch. Definitively much less than even a pickup or tractor's wheel. Practically no compaction from a dozer.
Those finishing dozers are good but I would use a grader and sheepsfeet to do it right, with laser guides, so as not to have low spots.
The dirt work you are contemplating will not cost much in labor. Since you seem to need to rent the machinery, go ahead and compare the cost with getting the whole job done.
For the digging, I'd lean towards a backhoe first. Bigger bucket to work with for starters. And if you run into tough stuff, you can use the backhoe end to dig it up.
Why exactly are you removing soil? You want your drive to ba ABOVE the ground around it, so it sheds water. Drainage is THE most important thing to consider if you want a long lasting roadbed, IMHO.
Life is like a dog-sled team. If you aren't the lead dog, the scenery never changes.
I guess a little more detail about what I'm doing would be in order. The drive way I'm putting in is going to be cement pavers. I've been reading about the problems with clay and know about the expansion and contraction problem. So I want to put a thick gravel bed under the pavers, at least a foot. I'll use one of the new geotec fabrics overtop of the large gravel and then put in crusher run and then a sand bed. From what I've read this seems like it should give me a reasonable drive. As far as drainage goes I'm hoping that a thick enough layer of gravel will act like a dry well. with pavers water is going to go down between them anyway. There will be very little run off from anything else due to the placement of the drive. As to my original question about using a Bobcat. It seems like it would be a lot of fun to learn to use one and I'm a person who likes to do things myself. That way if it doesn't end up like I wanted I can only blame myself. But I will check on prices of having someone else do the job.
If there are big trees around you will find the Bobcat has trouble digging up the roots as opposed to a backhoe. I also find that a tractor with a box is better at leveling a drive, and it would be the best at spreading the gravel and sand too. If you are going to have as much gravel as you state (12 inches) you might consider renting a compactor also. Compact your subsurface materials every four inches rather than spread out 12 inch depth and then compact.
To the response on not using finish dozers for compaction, I agree. We see about 3% percent compaction above what we get with sheep's foot due to bigger dozers, D7's, and 627 pans running on a job site. Pans are a lot heavier on the spot load than dozers.
To OZTOL, if you're going to rent it yourself get a backhoe, you'll be much happier. Those little bobcats are for s*&@ honestly I can dig with a shovel almost faster than they can. A cat 416 is a lot easier to use.
remodeler
O.K. you in my field of living now. If its a fat clay, the type that swells when wet undercut and either a gravel or sand. They are both suitable. if its a clay sand mixture what alot of people call clay then cut to grade and place. geofabric are only neccassary if its a swampy or watertable type elevation..
As far as equipment, doser, track hoe, rubber tire hoe, bobcat(slow) they are all good. me, I woud use a tractor with box blade. That is what most contractor use around here.
It mainly depends on the subgrade material, wheather its a fat clay or mixture, please describe the material when dry and wet also color. then I can offer more information.
johnnie Browne soil tech 23 years
The best employee you can have but you wouldn't want him as a neighbor " He the shifty type"
Forget about the Bobcat. It's wheelbase is to short, and is not made or setup for cutting grades. I've used a Bobcat before on a job smaller than yours and it was a nightmare.
If you're going to do it yourself get a tractor with front bucket with teeth and a box blade scraper scarifier on the back. You'll want to lower the rippers on the box to break up the soil. Make sure you have full hydraulic controls for the box. You'll want to be able to just move a lever and have your box tilt to be able to cut fine grades. If you get a diesel tractor at least 40 to 50 hp you should have a good chance at doing the job.
Remember to always travel with the bucket in the low position, especially with a full load in it. It's real easy to tip a tractor. 75% of all serious farm accidents are related to tractors. Read the operators manual, front cover to back cover and learn how to set the angle of attack for the front bucket. If you don't do this you'll either just skim the top of the soil or just start digging holes instead of cutting nice grades.
Have fun, don't kill yourself, and good luck.
Cork in Chicago
For what it's worth, doing a smooth and level job with a Skid Steer (the generic name for a Bob Cat) is a lot tougher than it would seem.. especially if it's your first time using one..
I went to John Deere's school for skid steers and can tell you after a week of running them all (well 12 differant brands) none of them will easily cut into compacted dry clay very easily it can be a battle with any of them.
You might need several differant buckets to do the job, a bucket with ripper teeth to break into the clay and a smooth bucket to level everything..
Compaction is another issue. a sheeps foot vibratory compactor will do the best job with clay but if you don't overdig you may not need to go to that step.. In that case an ordinary smooth drum vibratory roller will do a nice job on your class 5 (or gravel base) and can even be used on the sand base..
One of the nice features of a brick style driveway is it's ability to resettle itself after the frost comes out in the spring..
I recieved 22 tandem dump truck loads of bricks once and they filled my driveway.. (How could I turn them down? they were twice fired clay paving bricks {fired in1903}that I got for two cases of beer) yet if I ever wanted access to my garage door I would have to do something with them..
what I did was lay them directly over the heavy clay in my driveway, oh there was a little sand mixed in with the bricks so in some spots maybe there's a inch or so of sand.. (more to level than any attempt to provide a base)
that was over 15 years ago.. in the spring as the frost goes out the bricks tend to be self leveling and if I should damage the base like last year when after the frost went out and a heavy month of rain I drove 30,000 pound forklift on them and left ruts, by mid summer the ruts were nearly gone and next spring you won't know where they were..
I've had plenty of cement trucks on them and they don't rut so it's only during rare brief chances can you do anything to them..
Just for information the brick road that these used to be was a major highway in the Minneapolis area for almost 90 years and they didn't show any significant wear when I got them..
If you are going to remove a foot of clay AND move it any distance, a Full size Back hoe with a front bucket will probably be the most efficient SINGLE machine.
An excavation contractor would tow his excavator or BH to the site with a dump truck. Then he could bale the clay directly into the dumper and move it wherever you want.
or if it is a large drive with a lot of soil to move he would maybe add a dozer to the operation.
But if it is just you by your lonesome....
Dig your clay out and pile it off to the side as far as you can reach with the Hoe.(an extend-a-hoe may help)
Then when you are done excavating, use the bucket to haul it where you want it.
If you don't have too many obstacles you can move dirt pretty efficiently.
Don't waste time grading or fussing, until you have moved all the stuff you want elsewhere, or it will take three times as long.
Find a jobsite where they are doing some major earthwork and watch how they do it.
A good excavation crew doesn't screw around can be educational tyo watch.Mr T
Do not try this at home!
I am an Experienced Professional!
Last year I did almost exactly what you are doing. I had a broken up 1" hand poured driveway on clay, no gravel underneath. I also wanted pavers. So I started out by hand, breaking up the driveway with a sledge and carting it to the back in a wheelbarrow. After a couple long weekends of that and serious back soreness, I called a Bobcat guy. He made quick work of the drive with a midsized bobcat.
After that, I rented my own skid steer to excavate the surface down to allow for fill. I got a New Holland brand which was much heftier than the Bobcats I've seen and even running on the rubber tires, it would excavate the clay with no complaints.
Here's where it gets good, after the excavation, I hired a contractor to lay the stone and build a foundation wall. In our contract, it specified that he was to fill 8" of gravel and lay 4" granite flagstone. Well, he brings the crew out one day while I'm at work and they lay the 4" granite flagstone the entire length of the drive (70ft), somehow forgetting the 8" of fill. When I pointed this out to him, he opted to lay a second layer of flagstone rather than taking up what he had already layed out, which seems ludicrous. So for my driveway, I have no fill gravel, but instead have roughly 9 inches of granite flagstone in two layers. I then got crushed limestone to fill in the gaps and it has a nice black contrast to the grey stone.
I've had full 18 ton gravel trucks down this drive and she ain't budging, at least not in my lifetime.
Regards,
Jon
Here's a shot of my drive referenced in the previous post.
One foot of red clay 10x100 ft long is a job for a full size four wheel drive backhoe with ag tires. Ripper teeth on the front bucket and a 30 to 36 inch back hoe bucket. This machine will be an awful lot of fun unless its on a slope towards your house .
Tim Mooney
hmmm..best machine to dig a driveway...for me that would be the phone ....to call someone to come do it for me.
(couldnt resist it) JC
I also want to move the spoil to another area of my yard for fill.
By my calcs, that's more than 35 cu. yards of dirt. That's a LOT of dirt to be moving with just some sort of front end loader.
You might want to consider a dump truck too.
OZTOTL,
I had a similar project done using a guy with a skid loader last spring. http://forums.prospero.com/tp-breaktime/messages?msg=30734.92
Should link you to pic's I posted. Took the guy ~8 hours to do the job. (dig down 12" and move soil to other areas and spead the gravel). But he was good. I think it would be cheaper to hire a pro for a day with a machine. Cost me $1500. including several large dump trucks of T& B gravel and topsoil.
Jon
Edited 12/23/2003 7:57:15 PM ET by WorkshopJon