Fabricated profile steel combined foundation pit supporting method

The invention belongs to the technical field of foundation pit supporting, and particularly relates to a fabricated profile steel combined foundation pit supporting method. After SMW construction method pile construction is completed, steel bars of a top beam are welded to the top end of a SMW construction method pile, and then the top beam is poured; steel bar connectors are spot-welded on the parts, extending out of the top beam, of embedded steel bars in the top beam, and are connected with profile steel enclosing purlins through screws; profile steel brackets are welded to one side of an embedded steel plate, profile steel supports are installed at the tops of the profile steel brackets, and the profile steel supports are connected with the profile steel enclosing purlins through bolts; steel support triangular pieces are arranged at the oblique crossing positions of the profile steel supports and the profile steel enclosing purlins; and profile steel stand columns are arranged in the centers of the profi