driveway edge repair

[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!