Driveway Challenge

[BruceWard]

I am building a house with a drive out basement garage. I need to establish a sold base for the long term use of the driveway and for short term use by concrete trucks. Most likely the concrete trucks will be front chute 6 wheel drive models. Originally I had planned to install a 6" base of locally sourced "city pit" over the existing rocky base. I have a 640' driveway with city pit that has not washed or been disturbed in any way since 2008. It has had 22 yard dump trucks, bull dozers, excavators from 18K to 80K pounds, a large vibrating compactor and many other trucks drive over and across it without damage. The city pit material is a white limy material with chucks of rock. After the house is completed the driveway will likely be covered with chip and seal or if necessary concrete.

This is the city pit driveway on a dry day

This is the area for the new driveway

This is the same area after some additional rock removal. The driveway will follow the excavator tracks in this one.

Another one looking a little further to the South (uphill).

The challenge is that water appears to be running out of the rocks in the driveway area. I plan to have an open ditch on the uphill side of the driveway all the way to the bottom to trap water running toward the driveway. I am considering cutting trenches diagonally across the driveway every four feet or so then filling the ditches with gravel and covering with geotextile fabric before applying city pit.

What do you think of this plan? What suggestions can you make?

I have two loads of gravel and 110 yards of city pit coming Monday morning so I need to form a plan and have all supplies ready be then.

 

[Ken45101]

It's hard to tell exactly the terrain along the driveway but if you are going to have a ditch running along the uphill side, I would put 12" pipe under the drive for drainage every couple of hundred feel to let the water drain through them. Your rock/geotextile idea may work but may also back up the water long term. IMO the drain pipes would be a more sure way of going. But I'm no expert.

Ken

 

[Craig Clayton]

Your land looks to be very high and able to have a good run off. I have found that in the spring when the ground is still frozen the water will go any way it can because it can not go down. The cuverts could still be plugged ( frozen ). I have studied many a spring run off in the country. I would suggest a thick bed for the drivway bed and the first spring your hard packed drive will be soft and for at least the next following spring.

Craig Clayton

 

[JB4310]

It's hard to tell exactly the terrain along the driveway but if you are going to have a ditch running along the uphill side, I would put 12" pipe under the drive for drainage every couple of hundred feel to let the water drain through them. Your rock/geotextile idea may work but may also back up the water long term. IMO the drain pipes would be a more sure way of going. But I'm no expert.

Ken

I agree with the pipe under as opposed to just gravel, you have to let that heavy run off out to the low side as efficiently as possible, otherwise you will have wicked erosion from the scour, and still force water under the drive.
I would put those pipes every 50 fifty feet or so in the worst area. Looks like you have enough slope and decent material to work with. IMO with the right storm water management you could save alot on fill and GEO.

JB.

 

[EddieWalker]

I'm all for the biggest pipe you can get. The gravel idea is just going to fill with sediment in time and not accomplish anything. A pipe, with a good slope to it, will outlive you and the house.

I would go put in as few pipes as I had to, and try to have a good ditch and collection area if possible.

Eddie

 

[BruceWard]

I did a bad job explaining the challenge. The driveway has excellent drainage everywhere but in the "Driveway Down Slope" shown in this diagram

This picture shows the area where the driveway will go down the slope

You can see some water in the picture above. This water seems to be draining out of the solid rock on which the driveway will be built. My challenge is not to route drainage across the driveway but to drain water that originates under the driveway. That is why I was considering using gravel in in diagonal cuts across the driveway. I could use small "holey" french drain pipes to achieve the same or perhaps better drainage.

This image looking from West of the house toward the driveway down slope may make it easier to imagine. The top of the diagram is South, the right side is West.

 

[Craig Clayton]

I am enjoying your picture layout. Would you mind showing on the map the full layout out of the property. If you could show NSEW, the lake side and distance to and the direction at 640' to the county road?
I did my own layout on a 10 acre property, I did not use CAD. I used a post pounder, T bars and a tape measure and the back of an envelope.
If you are the owner, builder, designer, banker there will be light at the end of the tunnel. Sometimes it is a very long tunnel.

Craig Clayton

 

[JB4310]

but to drain water that originates under the driveway. That is why I was considering using gravel in in diagonal cuts across the driveway. I could use small "holey" french drain pipes to achieve the same or perhaps better drainage.

Definitly use the perforated pipe not just stone. 4-6 inch pipe set in 3/4 to 1 inch crushed stone (uniform sized aggregate). You want the pipe to run Perpendicular to the slope to intercept the water moving down grade. If it's real bad maybe a pipe every 10 ft. if not so bad every 20-25 ft. pipes should empty to daylight on sides of driveway into a swale.

JB.

 

[BruceWard]

The driveway down the slope has an inside radius around 20' to 25'. I am waiting to hear from the concrete company on what the turning radius is for their 6 wheel drive Terex trucks. The slope area I am concerned with is less than 40' in length.

 

[BruceWard]

I am back with more pictures. I painted lines on the ground today for a 21' inside, 36' outside radius driveway that would be 15' wide. I hope to be able to cut down the uphill side and build up the downhill side with city pit on Monday.

Starting on level and flat up top banking into the downhill curve

Having completed the first 45 degrees and truely on the down slope

Completing the last 45 degrees and back on level ground 9' below where we started

In this one I stepped back into the woods and took a picture looking toward the down slope area showing the top, curve and bottom.

This picture was taken from the bottom looking up