Driveway sinkhole repair

[Jaspel]

Looking for some advise on my parent's driveway. A crack turned sinkhole has been forming at the corner of their asphalt driveway where it terminates to the garage. No apron and has a gutter downspout within a couple feet of it, however it does appear to drain away. Suspect the downspout is freezing up in the winter.

Last time I looked at it, the opening was around 3" wide by 24" long and 30" deep with a large enough cavity to see several blocks in the footer. This is a Minnesota (3.5' frost line) modern attached garage. No apparent damage to the garage floor yet. Sorry, no pictures at the moment.

Thinking the correct thing to do here is to have a concrete apron and drain put in, however they have been putting this off for three years now. Old Man has been talking about throwing in some sand or readymix, but I'm concerned that he is letting this go. Water drainage aside, would filling with sand and coldpatching be adequate here?

 

[JamesW84]

Pictures would help a ton. It almost sounds like the backfill from the footing excavation is separating.

if it's a true sinkhole, sand will just eventually work it's way down and the same thing will happen again. The way sinkholes are repaired is to put as large of rock as possible (in large sink holes, large 12" plus rip rap is used). Then you put smaller on top of that and smaller and smaller until you get to the top where it's topped with topsoil or concrete.

Not an expert, but I have 4 1/2 acres that's classified as a sinkhole, so I've looked into it a bit.

 

[tarmy]

I would dig it out to examine the waterproofing on garage foundation to make sure it has not failed...and to make sure erosion has not occured under garage. You need to determine the source and prevent it from recurring.

The fill, in my opinion, would be based upon the adjacent material, stabilty of situation of remaining fill material, how deep the clean out is and what the ability to compact it is.

Good luck...

 

[Bretny]

Extend the down spout way out past the hole. Fill the hole with gravel and see what it does.

 

[Pluribus]

Not knowing all of the site conditions, I can't say what's best for your situation. Anecdotally, I fixed one on my driveway by digging down a little bit, then filling the hole with large bits of broken cinderblock and rock. Filled in around irregularly shaped bits in the hole with gravel, then topped it with the normal driveway gravel. Hasn't settled a bit in several years.

More likely, you'll need to find out where the water is coming from and divert it somewhere else first, then fill/compact your hole before resurfacing.

 

[Jaspel]

It almost sounds like the backfill from the footing excavation is separating.

Yeah, that sounds about right. Perhaps sinkhole is the wrong word- but then it has to be going somewhere..?

 

[Bondo]

Yeah, that sounds about right. Perhaps sinkhole is the wrong word- but then it has to be going somewhere..?

Ayuh,..... Go look where the down-spout drain daylights,.....

You'll probably find the lost fill there,......

The quick, 'n easy fix is fill the hole with concrete to within a couple inches from finish grade, then cap it with blacktop to match the driveway,.....

 

[Jaspel]

Diagram

I think this came out of a poor downspout. It drops between a sidewalk that steps up above grade to the front door. It doesn't go underground, just spills out on the sidewalk.

 

[kbs2244]

You have the right idea.

You need the reroute the rain water.
Maybe reroute the gutters to the far corner of the house?

It may take oversized gutters, but that is easier than digging.