Construction method and structure for heightening core wall dam into concrete faced rockfill dam

The invention provides a construction method and structure for heightening a core-wall dam into a concrete faced rockfill dam, a heightened rockfill dam body is arranged on the downstream side of an original dam body of the core-wall dam, the center line of the constructed concrete faced rockfill dam is located on the downstream of the center line of the original dam body, and a concrete diaphragm wall is arranged on the core-wall part of the original dam body for the concrete faced rockfill dam. A dam crest structure of an original dam body is dismantled, a concrete toe board of the face rockfill dam is poured on the top of the original dam body with the dismantled dam crest structure, a concrete anti-seepage wall is connected with the toe board through a connecting plate, the toe board is connected with a face plate, and a complete anti-seepage system is formed. Construction can be carried out on the premise that the safety of the dam is guaranteed, investment for heightening the dam is saved, and normal op