Flange type large-caliber PE pipeline under-pressure restoration structure and restoration method thereof

The invention relates to a flange type large-caliber PE pipeline under-pressure restoration structure and a restoration method thereof. The flange type large-caliber PE pipeline under-pressure restoration structure comprises PE flanges provided with necks at middle subdivisions, loose flanges with middle subdivisions made of a metal material and flanges with necks, wherein electromagnetic insulation heating wires are inlayed on the inner arc surfaces and subdivision faces of the PE flanges, temperature measurement probes are embedded on the inner arc surfaces and subdivision faces of the PE flanges, the two PE flanges are respectively arranged on two sides of the damaged position of a PE pipeline and is fused with the PE pipeline through electromagnetic thermal melting to form a whole. The loose flanges are installed on the necks of the PE flanges in a sleeving mode and form a whole through the subdivision faces welded in a paired mode, the flanges with the necks are arranged on the PE pipeline in a sleeving mode and form a whole through the subdivision faces welded in a paired mode, and the flanges with the necks, the loose flanges and the PE flanges are connected through bolts in a sealed mode. The outside of the PE pipeline between two flanges with the necks is sleeved with a metal tubular product, two ends of the metal tubular product are welded with the necks of the flanges with the necks, and a sealed cavity is formed around the damaged position of the PE pipeline. By the adoption of the flange type large-caliber PE pipeline under-pressure restoration structure, any damaged position in any shape can be restored under the pressure in an operating state of the PE pipeline.