First, you need to make sure that it is in fact a rat/rodent burrow you are observing around your home.
Rats create underground pathways or burrows from their nest to food sources and to escape predators. These burrows are often located under bushes or other types of dense vegetation. Rat burrows usually contain a main entrance and 1 or 2 exit holes away from the main entrance. Check along walls and grass for runways. Rats run along the same