Prestressed grouting pipeline plugging device and grouting method

The invention provides a prestressed grouting pipeline plugging device. The prestressed grouting pipeline plugging device comprises a fixed grouting hollow pipe, a rotatable propelling grouting hollow pipe and an iris valve arranged at one end of the rotatable propelling grouting hollow pipe. Wherein the outer diameter of the propelling grouting hollow pipe is smaller than the inner diameter of the fixed grouting hollow pipe; the iris valve comprises a fixed disc and a plurality of rotating blades, the fixed disc is provided with sliding grooves used for enabling the rotating blades to rotate to be opened and closed, the rotating blades are connected with the propelling grouting hollow pipe, and the rear ends of the rotating blades are provided with first protruding pieces matched with the sliding grooves; the multiple rotating blades are of a fan-shaped structure and are arranged at one end of the propelling and grouting hollow pipe in the mode that the plane formed after the front ends of the multiple rotat