walkway sinking

[dhensel]

We have a 30,000 gal. inground, vinyl-lined pool. The concrete walkway (3 feet wide) around the pool is sinking at the edge that is away from the pool. It has sunk about 6 inches and slowly continues to sink. The curved section (where the liner tucks in) and the walkway are starting to pull away from each other. It is doing this around about half the pool. Do I need to have a foundation person look at it or what? Thanks!
Don