Driveway sinking

[hawkeye08]

We have clay soil. 100' driveway, put gravel down to avoid mud, made ruts in gravel and gravel disappeared... after a couple of years, torn it out down about 10", put DOT road fabric down), put gravel down (some bigger stuff first, then the 5/8-, no problems since (actually had it paved a few years ago to make it easier to clear snow and reduce tracking into house...

Some new neighbors put many truck loads of big rock, crushed, etc and still have a problem driveway... we told them they need fabric but they rather spend money on gravel truck loads..

 

[oosik]

On my mile long gravel driveway there is one spot, about 60', that would get muddy in the spring and again in the fall. The neighbor and I dug and filled on that dam spot for years. Finally one of us had a brain fart - dug a nice deep ditch on the uphill side of the driveway - diverted all the water coming onto the road to a low spot away from the road - problem solved. Even with his commercial backhoe we really never got to anything you would consider hard - just a mile of grey clay. A backwash from one of the great floods from Lake Missoula.

 

[jaxs]

On my mile long gravel driveway there is one spot, about 60', that would get muddy in the spring and again in the fall. The neighbor and I dug and filled on that dam spot for years. Finally one of us had a brain fart - dug a nice deep ditch on the uphill side of the driveway - diverted all the water coming onto the road to a low spot away from the road - problem solved.:drink: Thass wut I bin tawkin bout,no water=no mud Even with his commercial backhoe we really never got to anything you would consider hard - just a mile of grey clay.And that is true of more places than not. A backwash from one of the great floods from Lake Missoula.

Kinda make's one feel like a fool after it's all over because the answer was right there all along.

 

[jaxs]

Good points. I'll add, a crawler tractor does NOT, I repeat NOT compact soil. By design it spreads it's weight over many square inches of track, totally against all compaction principles.

The landowner can compact it with his bare feet if he like's,the crawler is to move dirt,lots of it if necessary. The point is a 50 horse power hobby farm tractor isn't suited to the task. Stated another way. Around here you can hire a D8 with operator for $150 per hour and they will move more dirt in 6 hours than 90% of tractors owned by members of this forum can move in a week.

 

[Firemanbuck82]

The landowner can compact it with his bare feet if he like's,the crawler is to move dirt,lots of it if necessary. The point is a 50 horse power hobby farm tractor isn't suited to the task. Stated another way. Around here you can hire a D8 with operator for $150 per hour and they will move more dirt in 6 hours than 90% of tractors owned by members of this forum can move in a week.

Proper compaction requires proper soil moisture and the proper equipment to compact. As stated, tracked equipment will not impart the required energy to compact the soil. Granular soils need a vibratory roller and cohesive soils like clay, need a sheep's foot roller to kneed the soil in place.

You can short circuit the process by driving large rock (3-6 inch) first into the soft soil until it bridges then finish with crushed rock. The woven geofabric with 12 inches of crushed is also a good way to go.

 

[EddieWalker]

So here is the issue and where I need some experience. I spread the third load on the area in front of the shop and around to the basement garage. Graded it all with the box blade and compacted it with my bobcat (also compacted the dirt underneath with my bobcat the best I could). Looked great! I noticed immediately after it got some moisture in it that when driving on it cars just SINK IN. I mean bad. Like nearly getting stuck in it. I am feeling a bit defeated at this point but I really need to get it fixed before winter gets any closer and sets in.

View attachment 527934

You are getting all sorts of advice, some I agree with, especially from Jaxs, others are very localized to where "they" live and not what I would do if I was where you live.

You said that you have a high clay content, which is what I was expecting from your pictures and your location. Soil that is mostly clay does "NOT" have a layer of organic materials, or topsoil. Do not try and remove topsoil when you do not have it, all you do is create a place for water to settle down into and sit. Kind of like digging a very shallow pond.

Since water likes to sit on top of clay, drainage is extremely important. That hill to the right of your picture looks like it's providing a lot of run off when it rains. You might also be getting a bit of a spring effect with moisture that soaks into the hill above, coming out where you cut into the side of the hill. Water goes down into the ground, then comes out where it can.

You are going to have to create proper drainage for this area. A big ditch is always best, but it requires the most work. Pipes work, but they tend to clog up over time.

How thick is the rock that you used? Is it road base rock with different sizes from a couple inches down to fines all mixed together? At a minimum, road base needs to be at least 4 inches thick. More is better, but if you go less, it will not interlock together and form a solid road that will shed water.

When you compacted it, did you add water to it at that time? If you compact it dry, it will appear hard, but when it rains, the water will soak into the rock and will make it soft. Just like you described. Once this water evaporates out of the gravel, and as you drive over it, and if it's thick enough, it will compact for you and become very hard.

If you do not have enough rock, no matter what you do, it will never lock together.

Fabric is for poor soils, wet areas and those in a hurry and not wanting to, or unable to prepare the soil. In most cases, it's not needed and just an extra expense.

To compact rock, you want as much weight on as small of footprint as you can get. I use my backhoe with a full yard of dirt in the front bucket, and drive over it with the front tires, over and over again.

 

[ovrszd]

The landowner can compact it with his bare feet if he like's,the crawler is to move dirt,lots of it if necessary. The point is a 50 horse power hobby farm tractor isn't suited to the task. Stated another way. Around here you can hire a D8 with operator for $150 per hour and they will move more dirt in 6 hours than 90% of tractors owned by members of this forum can move in a week.

Yep, just didn't want readers to think the crawler would compact soil. If making a large fill with a crawler you better have another tool there to compact as you go.

 

[nrc17gto]

How thick is the rock that you used? Is it road base rock with different sizes from a couple inches down to fines all mixed together?

When you compacted it, did you add water to it at that time?

This part was all 1.5 crusher run as they called it. So 1.5" gravel down to fines. I actually had it about 6" thick. Later made it thinner in an effort to help.

It was dry when I compacted it. After it rained it all got wet and has stayed wet since. I am hoping it rains soon (sounds odd to say) so that I can see how it all flows. I have the 555d that I can cut some ditches with to divert all I can. I think the thing I am going to have the most problem with is getting that area in front of the shop to divert water off that falls there. It is close to 2000 square feet I would say.

Thanks for the advice!

 

[cqaigy2]

Did you remove all the organic material where the driveway is before laying down the crusher run? If you still have an organic layer, which it sounds like, nothing short of full removal or concrete will fix the problem. A road needs to be brought down to a stable surface and then built back up.

This forrest service manual is one of the best sources of information on how to prep, crown, drain, and maintain a road.

https://www.nrs.fs.fed.us/fmg/nfmg/docs/mn/roads.pdf

Interesting read, thanks.

 

[mapper]

Many years ago I learned while working for a large timber company, that when you build a road, it works best to build the subgrade and ditches, then let it settle and dry out for a period of time before adding rock and gravel. Soils with high clay content will tend to turn into soup when disturbed, but will settle after drying out some.
I know it's a bit late now but for your driveway to the shop if you get the earth work done now then try to stay off of it until spring or summer, then add rock you will probably have a lot more success.
If you want to pave it, you will still need a gravel base for drainage, concrete or asphalt on clay will crack and move around as the moisture content in the clay changes with the seasons.
There is a lot of good information in this thread, lots of experience among the posters. Good luck with getting your driveway done.