Chipmunks are called ground squirrels for a reason, they are the ones that dig burrows, so that is your target. I am about convinced chipmunks and squirrels are planning an uprising some day. When I pull up to my house, it looks like I have created a refuge for them. I've seen as many as 8, just hanging out in the front of my house watching me pull in. I have holes all over my yard from them. I thought about the bucket trap, but that is a bit extreme. Last year I raked up all the walnuts that fell and the number seemed to drop a bit. This year I cut the tree down, for other reasons, but it'll be nice not to have to rake up. Unfortunately, I have acorns too and those aren't as easy to clean up.
Finally to the point: If they are getting into a specific burrow dig up a little bit around the area and level it out. Then lay a large piece of hardware cloth (wire mesh) and bury it. Pack the soil well. U can also try cayenne pepper, but I have heard mixed results...may need habanero or ghost peppers to light em up.