Staged tensioning method for arch support opposite-pull rods of continuous arch bridge

The invention provides a staged tensioning method for arch support opposite-pull rods of a continuous arch bridge, which comprises the following steps that embedded pipes used as opposite-pull rod holes are embedded in corresponding arch feet of arch supports, opposite-pull rods are arranged in the embedded pipes, and two ends of each opposite-pull rod are respectively connected with two adjacentarch supports; before a single-span arch ring is poured, the opposite-pull rods are pre-pulled to be tensioned to a first preset value; after the single-span arch ring is formed and before an arch structure of the single-span arch ring is constructed, the opposite-pull rods are loaded and tensioned to a second preset value, wherein the opposite-pull rods can be tensioned according to multiple stages of preset values, the preset values are increased stage by stage, and the difference value between every two adjacent stages of preset values meets the controllable requirement of the middle arch support in the action of t