Pier column supporting and protecting method for existing viaduct close to deep foundation pit

The invention relates to the field of bridge pier columns, in particular to a method for supporting and protecting an existing viaduct pier column close to a deep foundation pit, which comprises the following steps of: hoisting cylinder steel supports by adopting a triangular bracket, arranging four cylinder steel supports on the periphery of the bridge pier column, erecting a shoulder beam on the cylinder steel supports, arranging a jack on the shoulder beam, and supporting the bridge pier column on the shoulder beam; when a downward force is generated when the bridge sinks, the jacks, the shoulder beams and the cylindrical steel supports around can share most of the stress of the pier columns, and the pier columns are effectively protected. Compared with a traditional pier column protection method, a reinforcing mode is small in occupied space, short in period and low in cost, the influence of surrounding environment restriction is overcome, the influence on a bridge structure is reduced to the maximum exte