I doubt it would cause the floor to fracture, but who knows...I'd probably dig, clean it out at least 4-5" deep and then consider using some hydraulic cement to plug it. To hold, it would need to be slightly rough and it would be good if it was flared some, so it would be like a tapered plug, with the smaller part at the top. Hydraulic cement sets up VERY quickly, and expands slightly when curing, so it makes a good thing to create a plug with.
To help minimize the problem, make sure that the landscaping around the house slopes away from the foundation for at least 10' and that any gutters discharge away from the house and that water doesn't pool next to the foundation. If you don't have gutters, you may want to consider adding some.