Deep foundation pit profile steel enclosure structure

The invention relates to the field of deep foundation pit support technologies, and provides a deep foundation pit profile steel support structure which comprises a plurality of pieces of I-shaped steel and a plurality of pieces of supplementary steel. The I-shaped steel comprises two parallel parts which are parallel to each other and a vertical part which is used for connecting the two parallel parts; the supplementary steel comprises a connecting part, a first abutting part and a second abutting part, wherein the first abutting part and the second abutting part are arranged on the two sides of the connecting part respectively, and the connecting part, the first abutting part and the second abutting part extend in the length direction of the I-shaped steel. The first abutting part abuts against the joint of the vertical part and the parallel part, and the second abutting part abuts against the joint of the vertical part and the other parallel part; and an included angle is formed between the first abutting