driveway edge repair

[mpowrd]

I just had a small landside take out some of the bedding at the edge of my driveway. A section of driveway about 20 feet long now has a gap below it about 1 foot high and 2 feet wide (going into the driveway). It looks like there's still good bed material directly under the asphalt.

Until I can get in there and figure out what kind of retaining wall and fill I'll need longer term, I want to support the edge of the driveway to prevent the asphalt from cracking and to help take some of the traffic load. Right now I can detour to the uphill side enought to avoid the voided area, but sooner or later the propane truck needs to get up there.

I read that I could use sand bags filled with a sand and cement mixture that could be stacked in the void dry, then wet down so they harded up. Do you think I could get the same result stacking paper sacks of concrete mix or do I need the porosity of the burlap sand bags to get them to bond?

Thanks for the advise.

 

[CurlyDave]

You are only looking at 40 cubic feet of material, about 1.5 yards.

I would think about what an architect would call "lean concrete" to fill it. About a 3 sack mix. This would be cheaper, easier to set, and faster both to set and to cure than sacks of concrete.

It is not nearly as strong as concrete, so it can be removed later for a better fix, but if it breaks up, the pieces all fit together and it still has some holding power.

* * * * *

I have both seen and read about paper sacks of pre-mixed concrete being stacked as rip-rap. The sacks are then held together with short pieces of rebar driven through them. The rebar and the fact that the sacks slump together holds them pretty well, especially after they have weathered for a few years.

The big advantage here is that the sacks can be individually carried into some pretty steep areas, and no forming is needed.

My back aches just thinking about this, and removal for a permanent fix is going to be lots of fun.

* * * * * *

You have good access to the washout. Check the cost of a concrete buggy full of lean concrete. Build or dig a primitive form and you will be far ahead of the sacks.

 

[mpowrd]

Thanks for the tips.

I might use a combination of sacks with rebar in the hard-to-reach area under the lip, then put a form down and pour from a buggy trailer on the outside.

I need to measure the actual size and see what the base looks like today. I'll try and post a pic or two later.

 

[ultrarunner]

Public works would fill burlap sacks with concrete and stack... some of the ones I know are 45 years old and still on job.

 

[crbr]

yes.....

 

[mpowrd]

Update:
Measured the void below the driveway edge and it's larger than I originally estimated. About 35 feet long, cuts in about 24 inches, and is 24-32 inches high.

I'm attaching some pictures of the problem area.

A friend locally that does tree and equipment work for me reckons that it might be cheapest to put up some forms and get a concrete truck and a pump in there so we could direct the concrete into the spaces with minimum effort.

 

[irvingj]

Have you considered some sort of stabilizing elements --maybe metal rods?-- pounded down into the ground prior to adding fill or concrete?

That's a pretty steep slope there; I'd be worried that anything placed under the road might be tempted to just roll out and down the hill with a little encouragement....

I notice that tree there seems to be doing a pretty good job of holding things in place on that end of the problem area.

 

[teg]

...so we could direct the concrete into the spaces with minimum effort...

What will keep the concrete from siding down the hill, too?

 

[beenthere]

I agree with teg, and looks like stabilizing that slope below the drive is needed first.

Has the appearance that water came across the drive and washe/eroded the hillside away. Is that a possibility?

 

[Egon]

As per the last two comments; before doing anything figure out what must be done to rebuild the side slope, stabilize it, Get drainage under control and resurface the road.

Hate to say it but it may be a little bigger/costlier project than initially thought if it gets a proper fix.

Forget the concrete and remedial action as that money spent will be lost. The pavement in that area will also be lost when rebuilding starts.

 

[ruren]

From the pictures it looks to me like things got saturated and the whole slope slid down the hill as one piece. I think you have some drainage issues that need to be addressed as part of your fix. If you just fill it in with lean concrete I'm afraid the water will build up behind it next spring and push the whole works down the hill again. I would consider improving or creating a ditch on the uphill side of the drive with a culvert to drain it under the pavement to the downhill side. Then fill the void you have with some well compacted gravel that can allow the moisture to drain without building up behind it. Probably more work than you would prefer, but it looks like water is your enemy and quick fixes rarely cure that sort of problem. Hope that helps.

Update:
Measured the void below the driveway edge and it's larger than I originally estimated. About 35 feet long, cuts in about 24 inches, and is 24-32 inches high.

I'm attaching some pictures of the problem area.

A friend locally that does tree and equipment work for me reckons that it might be cheapest to put up some forms and get a concrete truck and a pump in there so we could direct the concrete into the spaces with minimum effort.

 

[MarkV]

That doesn't look good to me. I believe I would get an engineer in to consult. Setting forms and pumping concrete would be good but without a stable base it could move again. Might be harder to fix properly the second time.

Good luck, hope you will update the post as you figure it out.

MarkV

 

[mpowrd]

Here's some more background:

The soil downhill about 100 yards from the driveway gave out and slid onto the county road below. With that support gone, the hillside slide down with it, lowering the level just below my driveway about 3 feet.

There isn't any evidence of water percolating through the the ground immediately below the driveway and the soil in the sunken area isn't that saturated either. There is a lot more water 50 yards or so downslope.

My immediate plan is to widen the driveway on the uphill side away from the slide so that traffic can be kept away from the damaged part until I can get someone experienced to look at it and design a solution.

I appreciate the input. You guys have confirmed what I thought when I took a better look at the situation yesterday which is that it is not going to be a quick fix.

 

[wvpolekat]

I think what you will end up with is some kind of retaining wall with a good anchor that doesn't rely as much on the hillside below. Around here they would drive I-Beams in vertically, then fill between them with timbers then backfill.

This could be done from the road with the right equipment, probably without even driving on the unsupported road.

The big challenge is going to be locking it into the hillside. Once you have that, supporting the road again will be easy.

 

[Egon]

There is a lot more water 50 yards or so downslope.

That is what probably caused the whole slope to slip.

Getting some knowledgable consultation in is a wise move.:thumbsup:

Or find an old Cat Skinner with a D9 who has wore out a seat or two on the big machines and tell him to have at it!

 

[CurlyDave]

I have to agree, the pictures look a lot worse than it sounded at the start.

Get an engineer to look at it. There is 100' of unstable soil below that drive.

 

[mpowrd]

Great input from everyone. I've had one experienced person look at it already and another will be there shortly.

Looks like a multi-phase project. This week I'm going to get a drivable surface on the uphill side of the driveway where (luckily) I have several feet of flat space. This will let us get driveway traffic on the solid section of driveway bed.

We're also going to do some temporary backfill packing under the driveway overhang to take the tension off it and help stabilize the existing bed.

A permanent, engineered solution will need to wait a month or two until everything drys out enough to work with. It will probably involve auger drilling some deep footings to anchor a new retaining wall with proper drainage and resurfacing the driveway.

I'll post updates and pics as things proceed. Thanks again for the sage advice.

 

[teg]

Ouch, that didn't sound cheap... It does sound like a good permanent solution.

 

[MarkV]

Ouch, that didn't sound cheap... It does sound like a good permanent solution.

My thought also. You do need to do it the right way the first time, the existing road going away would not be the right way and surely end up costing more.

Living in Georgia, we hear of slides in Cal. often when you get big rains. Is this common around your area of California?

I hope you will update the post as you work on a solution.

MarkV

 

[moored4]

Keep us Updated and send pictures as you can get to it. Good Luck! We had a similar situation, Luckily it was on the counties part of the road not mine!