Pile group underpinning structure for underpinning shield tunnel crossing bridge pile foundation

The utility model discloses a pile group underpinning structure for underpinning a shield tunnel crossing bridge pile foundation, which is connected with a bridge provided with a box girder, a pier, an original bearing platform and an original pile foundation, and comprises an underpinning bearing platform, a plurality of underpinning piles, a supporting structure and a reinforcing structure, the multiple underpinning piles are symmetrically and evenly arranged at the bottom of the underpinning bearing platform, the supporting structures are located on the two sides of the underpinning bearing platform, the reinforcing structures are arranged below the underpinning bearing platform, and the reinforcing structures wrap the underpinning piles and the supporting structures, namely supporting, retaining, reinforcing and protecting structural measures are adopted for the side wall of a foundation pit and the surrounding environment. The construction safety of the underground structure and the safety of the surroun