Access hole reinforcing device and rapid reinforcing method for existing bridge concrete box girder

The invention discloses an access hole reinforcing device and a rapid reinforcing method for an existing bridge concrete box girder, the box girder is excavated to form an access hole communicated with an inner cavity of the box girder, the access hole reinforcing device comprises an inner ring plate, the inner ring plate comprises two arc-shaped plate blocks which are detachably spliced together, the two arc-shaped plate blocks are attached to the inner side wall of the box girder, a ring hole of the inner ring plate is aligned to one end of the overhaul hole; an outer ring plate which is attached to the outer side wall of the box girder, and a ring hole of the outer ring plate is aligned to the other end of the overhaul hole; and multiple opposite-pulling assemblies which comprise perforated rods and pulling rods, the perforated rods are arranged in the overhaul holes in a penetrating mode and abut against the inner walls of the overhaul holes, the two ends of each perforated rod extend into ring holes of t