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.

 

[tcreeley]

Money has never been plentiful and I've always looked for shortcuts. My barnyard and riding area used to be a small field. It was all clay dirt with poor run off. I had all of the horse manure I wanted and I used that to create the slope that I wanted, grading it carefully over 2 years. It was still soft when wet, but there was nolonger clinging mud. Over the next two years I spread 16 large truck loads of gravel over the manure. The gravel hardened up after a rain or two. The entire ares slopes and it is surrounded by ditching. It is good year around, solid surface, snow melt, rain, etc.. The key was planning the run off and getting rid of the water with ditches. The perimeter ditches stop the water from percolating in from the side as well. - The point is that even horse manure can work for fill under gravel- if the slope and drainage is taken care of!
- In some areas the slay is blue and 2-3 ft thick above the hardpan.
6" below the surface in the spring I have standing water when I dig a hole throughout our property..

 

[bspeedy]

From the picture, you have a building built in a bit of a low spot. If I owned it, I would change the grade coming from the point from where the pic was taken. Cut the bank down in front of where the vehicles are parked. Swale that and direct it to a culvert under the driveway to the left. The other side (rh side in the pic) must have water diverted from the shop / driveway area as well. This water will be swaled around the shop and out the back. Water coming out of the culvert must be diverted from the shop. You have a funnel that is dumping all the water from uphill into your shop parking area. I think it will take lots of dirt work and probably some fine tuning to get it right. This job can be accomplished with smaller equipment, but it will take a while.

 

[bluelou212]

Hi TBN!

I admittedly did not know a lot about building a road when I started clearing and getting ready for the shop build a long time ago. So now that we actually have the house built (for about a year now) I was hoping to get it in a lot better shape for the winter. The driveway (road) is about 1800' long in total. The first section has pretty large rock on it with fines that has held up pretty well but there were some problem spots where water was running down the middle (because I was a newbie) on the second section so I created drainage on the sides and a few small trenches cutting across the driveway to divert it to those trenches where necessary. I should mention that some of this driveway is running uphill/downhill so the water can really gain some speed. I also had water ponding in front of my shop and no driveway yet running from the shop to the basement garage. So I dug out (also expanding) all of the area in front of the garage to get it graded so that it would better drain the proper direction away from the driveway. This got rid of the ponding issue. I then had 3 truck loads of 1.5" crusher run brought out. Two of these were spread on the second section to the shop, the third stockpiled. After boxblading the two spread loads that section of driveway is working pretty well. I have to do just a bit more to it but is way better than it used to be.

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. Here are some options I am thinking of.

- Get much larger rock (maybe 2.5"-3"?) and spread it all across this area and compact, wait til spring and put the crusher run down if needed
- Get driveway fabric and put down then rock
- Concrete the whole area (not the whole driveway), I want this eventually but not sure I can afford it before winter
- Asphalt the whole area (should be lower cost than concrete but got an estimate on the entire driveway of $42k!)

Any other thoughts are welcome. Our dirt area in the back of the house is all muddy all the time too, very frustrating. I am thinking that may be because of our high clay content in the middle TN area. Not sure if I sow some good grass out there in spring if it will tie it all together or if I need to get top soil first.

Attached a picture. The driveway over to the basement garage goes off to the right but it did not have gravel on it yet.

Thanks as always,
Nick

View attachment 527934

I haven't read this whole thread but I was in the commercial asphalt paving business for several years and my family has been in it since the 60s. From the pic, it appears some of the surrounding elevations are higher than the parking area. The problem is likely either weak subbase or hydrostatic pressure from a high water table or coming off a higher elevation.


Consider drain tile (schedule 40 pvc, perforated) in a trench with 3/4" stone and lined with permeable fabric. Id see how that works with an Item #4/d.o.t. #304 or whatever ur state calls it (you want the state spec, not 'crusher run'). If it settles and drain well, assuming organic material is removed, then, maybe pave a year or so later

 

[blackrams]

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.

I'm not an engineer but, I have worked with road construction a lot in my career as a safety professional. The above quote is the best advice I've seen given. Water is a roads worst enemy. In every road project I've been associated with, the engineers always address water issues first. They always find a way to drain water away from the road bed before they do anything else. Then, they set a based (some times using a highway fabric material, some times not) but, they always start with large gravel and work their way to smaller gravel compacting at each step. But, as I said, they address water drainage issues first.

When I built my shop, it's about 300 feet from the asphalt. I had the contractor dig down and then follow the same steps. I also installed a French drain from the shop down the drive to the ditch. Haven't had a problem in 10 years and don't expect any. I put concrete from the asphalt to the shop and then put a gravel parking spot for my goose neck trailers beside the shop. No sinking or rutting in all the time since being built.

Rams

 

[nrc17gto]

It has been a little while since I posted in here and I have a plan for fixing this area. I just have to wait for spring to get here and all this rain in TN to go away. I bought some geotextile fabric to use (in addition to other things I am going to do ) in the area in this thread. Here is a bit of a follow up question.

The rest of my driveway from the snow/ice/rain/thaw has gotten pretty muddy in areas as well. Sinking into the ground. What are your thoughts of putting this fabric over the existing driveway (after grading some) then putting another layer of rock down? My thinking is this would stabilize the soil/rock that is currently there and then the new layer should stay in good shape going forward. I am afraid if I just put more gravel in these areas it will just sink in again over time.

I wish I would have put the fabric down before I ever started but not the first driveway mistake I have made....

Thanks for your thoughts as always.

Nick

 

[tcreeley]

Nothing will really do the job until the water runoff and drainage is figured out. Tackle that and you may not need to add any fabric or fill. Slope the surface for easy runoff and ditch the perimeter, adding culverts to move the water away.

 

[nrc17gto]

Nothing will really do the job until the water runoff and drainage is figured out. Tackle that and you may not need to add any fabric or fill. Slope the surface for easy runoff and ditch the perimeter, adding culverts to move the water away.

Thanks for the reply. I should have clarified a bit better I suppose. The majority of the driveway is doing pretty good with water run off after my last effort. The freeze and thaw that we had and we have had a ton of rain around here has just totally saturated everything and the gravel has sunk into the clay/soil. This is where I am thinking I could put the cloth on top of the existing road bed before adding another layer of gravel to prevent any further sinking.

Nick

 

[EddieWalker]

The fabric will help a poor area, and speed up the time you can use a driveway, but it's not going to solve any problems. Most of the time it's used as a placebo to make people think they are doing something, when they really haven't.

If you lay down the fabric, you will still need to add at least four inches of road base gravel over it for it to lock together and become solid.

If you have a bad spot, you will still have a bad spot after you put down the fabric and 4 inches of rock.

My guess is that you don't need four inches of rock over your entire driveway. To properly fix your wet spot, you either need to wait for it to completely dry out, all the way down, or you need to dig up the mud and replace the soil with dry soil, compact it, and then add rock to the top of it. Mix the new rock with the old rock of the road, compact it and then get it wet, and compact it again.

Build it up so water runs away from this bad spot, and in a year or two, you won't remember where it was.

 

[Snobdds]

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

I have posted this before, but it's worth mentioning it again.

Have you dug a hole to see how far the clay layer goes down?

 

[Jstpssng]

We use the geotex to go across bogs with 100,000 log trucks; I think that you are on the right track. Rather than rock, after grading I would put 6-8" (after compaction) of good gravel on top.