Temporary bridge covered excavation method for constructing box culvert below traffic ground line of operating track

The invention discloses a temporary bridge covered excavation method for constructing a box culvert below a traffic ground line of an operating track, which comprises the following steps of: constructing supporting piles and pile top beams at two sides of the existing line, temporarily removing the line, and constructing prestressed concrete box type beams on the top beams to form a temporary bridge supporting system to be used as a temporary supporting structure of the line; and then, recovering the line, excavating soil bodies at the lower part step by step under the protection of the temporary bridge supporting system, and casting the box culvert structure in the field section by section. In the construction process of the box culvert, stress conversion of the supporting piles needs to be carried out, partial supporting piles are removed to enable the box culvert to become the supporting structure of the line, and the top beams and the constructing prestressed concrete box type beams are reserved for the permanent supporting structure of the line, thereby reducing the influence of construction on the operation of the traffic line of the existing track.