Polyurethane Foam is grout is an ideal product for use inside finished buildings and confined areas. Besides the benefit of a smaller hole, the grout cures in approximately 15- 20 minutes and will retain its cured shape and form.
If hole appearance or size is a concern (i.e. exposed aggregate driveways or sidewalks) then this method may be more preferred.
If your base material under your slab is in water and saturated then traditional mudjacking method would be better suited for your repair.