The sidewalk leading up to my front door developed what looked like a sink hole under it about a year ago. Since then, an animal of some kind has made the hole even bigger and it now runs as a tunnel under my pathway.
QUESTION: How to I fill this hole most effectively? Obviously it would be great if I could do it cheaply and without busting up the sidewalk.
CONCERNS: I like in Omaha, NE. We have extreme winters and summers. I thought about pouring concrete into the hole, but I'm concerned that it would expand under the sidewalk and cause buckling and cracking. I also thought about filling it with just dirt and sand, but I'm concerned that I won't be able to get the hole filled directly under the middle of the sidewalk, thus not supporting the weight load put in the walkway.