The invention relates to the technical field of
bridge maintenance, in particular to a
repair method capable of effectively treating serious defects of a bottom plate of an operation small
box girder bridge, which comprises the following steps: S1, preparation work: comprehensively checking a small
box girder, determining the damage range and degree and marking a damage area, S2, forming a cleaning hole and a mud jacking hole, and S3, carrying out construction of the cleaning hole and the mud jacking hole. The method comprises the following steps: S1, determining a small
box girder to be repaired, forming cleaning holes in a web plate and a bottom plate of the small box girder, and forming a grouting hole in the bottom plate of the small box girder, S3, cleaning the small box girder, and removing loose concrete and abnormal materials by extending a high-pressure water gun into a cavity of the small box girder to enable an interface to be fresh and rough, S4, carrying out
pressure injection of a grouting material, and S5, an outer formwork is installed at the bottom of the beam, the periphery of the outer formwork is sealed through
sealant, it is ensured that grouting materials cannot leak in the
pressure injection process, after sealing is completed,
cement-based grouting materials are injected into an inner cavity of the small box beam in a segmented
pressure injection mode through the grouting holes, and the thickness of a repairing layer of each segment is controlled, and S5, the outer formwork, the plugging cleaning holes and the grouting holes are removed.