Driveway sinking

[nrc17gto]

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

 

[Snobdds]

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

 

[nrc17gto]

Hi Snobdds,

Yes, there was nothing but dirt there and some larger rocks before I put the new gravel down. It seems to just be sinking into the dirt and not forming a good base as I had hoped.

Thanks,
Nick

 

[Snobdds]

I added a FS manual which will give you some good ideas. The forrest service put a lot of time, research and money into developing roads. Good read if nothing else.

 

[747driver]

I agree with Snobdds thoughts. You need to remove the crusher run and then dig down to solid stable ground. I always put down a layer of 3/4" stone first and pack it down. Then follow with a layer of crusher run, which will work its way down through the 3/4" enough to give you a firm road.

 

[ovrszd]

Some dirt cannot be compacted with any hope of longevity. Also, moisture content in the dirt at the time is critical. Too dry is as bad as too wet. Actually, in some ways it's worse. Dirt that is too wet will tell you it's not compacting the more you try to work it, will get spongy. Dirt that is too dry will fool you. It will display characteristics of a great compaction. Then the first time it gets rained on it will show you that it's not compacted well at all. I elevated 1/4 mile of roadway, in some places 15ft, this Summer. Dirt was too dry. Compacted great at the time. First rain it showed me it was not compacted. Finally with traffic and continuing to add gravel I've got a solid roadbed. But don't get over to the shoulder edge!!!!! Still soft there.....

 

[LouNY]

You are in for a learning experience.
Rocks, dirt, clay and water. If your base soil is high in clay content and you get high moisture content from normal water movement
you will always have problems. Above grade water is somewhat controllable by ditches and drainage, water that migrates thru the soil
is extremely difficult to control, sometimes drain tiles and gravel filled ditches can divert it from areas you are concerned with.
Where I live we have clay and hardpan when it becomes saturated it loses all support ability, my driveway has been in use for 50 years
and depending on the soil moisture some places will become quite elastic and non supportive. In the spring when the ground thaws I have
3 locations that will actually move under foot, when a vehicle drives on it, it will flex downward from the load and then float back up, this has had
gravel, crusher run and rock added for years the stone seems to actually migrate downward and the hardpan clay upward, highway fabric has been the
only somewhat permanent solution I have seen. My recommendation would bet to lower the grade 8-10 inches from your desired final grade put down
heavy road fabric and cover with gravel or stones and rock dust, some places may need stone and drain tile to try and dry it out. One problem with
road fabric is it will allow the road base to migrate downhill on steep grades.
Good Luck

 

[tcreeley]

From the picture it looks like the ground is sloping toward the front of your shop. That would channel water there before it worked its way to the side. I'd suggest drainage ditch sloping around your drive and crowning your drive to remove water before it soaks in and creates a below surface muck spot. -Drainage ditches/culverts around the perimeter of the drive and shop to channel water away around what you want to stay hard and dry might work to reduce flowing surface and below grade water.
Goodluck.

 

[Tompet]

Until you get a better base that is stable, I wouldn't think about concrete or asphalt. Last year I put in a few hundred feet of a new drive and where I pulled several stumps, I put in a couple tons of limestone rip rap (5"-12" large stone) in each hole then #1-2 limestone overall, which has been completely stable.

So other than a big excavation...adding larger #1-2 stone (different names different places) and letting that settle with possible fabric and more stone is something to consider along with grading/drainage as mentioned.

 

[jaxs]

The problem isn't with the material you are putting down. You must divert all water run off from other areas before it reaches your drive then give rain that fall's on the drive a way to run off BEFORE laying down material. If drainage is bad,you will never have decent driveway or parking. A word to anyone planning to build on undeveloped land,do all the grade work and create drainage BEFORE doing anything else. This is a job for a crawler tractor. A newly compacted dirt drive should be at least 12" higher than surrounding area before laying the first rock.