Pit-in-pit supporting structure at edge position of deep foundation pit

The utility model discloses a pit-in-pit supporting structure at the edge position of a deep foundation pit, which comprises a profile steel cross beam arranged on one side of the pit close to the edge of the foundation pit and reinforced concrete cross beams arranged on other sides of the pit, the profile steel cross beam is placed on the top of an enclosure structure of the pit, and the back side of the profile steel cross beam abuts against a supporting pile of the foundation pit. The reinforced concrete cross beams are poured on the top of an enclosure structure of the pit-in-pit, the reinforced concrete cross beams and a pit bottom cushion layer of a foundation pit are poured into a whole in a downward turning beam mode, and the profile steel supports are arranged between the profile steel cross beams and the reinforced concrete cross beams on the opposite sides of the profile steel cross beams. And the other end of the steel plate is welded with a pre-embedded steel base plate embedded in the reinforced