I have an interesting problem that I'm not entirely sure how to solve. The driveway to my garage has been lifted up to the point where large portions of it are now hollow underneath. Let me describe the driveway first to help you understand the issue. The driveway is in two planes - the first is flat (well, it should be and probably once was) and it extends out from the garage about 10 feet. From there, the driveway slopes down to match the grade of the slope in front of the garage - the length of the down slope portion is about 17 feet. The width of the entire driveway is about 30 feet.
Now the problem: the point at which these two slabs meet is being vaulted/pushed upwards, which has created large voids of hollow space under the driveway, running from one side to the other. You can see the space from the side and there is probably a good 3 - 4 inches of void between the slabs and the gravel base. The lifting is so great that the (previously) flat slab is no longer flat. I placed a six foot long level on this "flat" slab, with one end at the point where the two slabs meet with the other end running back towards the garage. At six feet back, it is off level by 1.5 - 2.0 inches.
I'm not entirely sure what has caused this lifting. There are no mature trees nearby, so it is not tree roots. The house is about 10 years old and this problem has existed since I bought the house about four years ago, but I think it has gotten a little worse over that time. Perhaps there are some issues from an improper pour from when the house was built - not sure about that. Perhaps the summer heat here in mid-Missouri caused it, but the problem does not go away in the winter, it's permanent. I think the most compelling suggestion I have heard has to do with the location of the house/driveway. The house is located at the bottom of a long steep hill and my driveway connects to the concrete road that runs down that hill. Someone suggested to me that the weight of the entire road on that hill is slowly pushing down on my driveway (like a concrete glacier) and has caused it to buckle up.
Open to any thoughts on the problem - but I'm really wondering what to do about fixing the problem. Would it be advisable to use a concrete saw to cut a small strip (perhaps 3" wide) out of one of the slabs where they meet in the hope that the two would then drop back down? Any chance that might work? Also, I'm not sure how dangerous that might be given the weight of those slabs?
I've tried to add a photo, but can't seem to get it to attach.
Appreciate any feedback.