Layered filling structure of rockfill material transition area of face rock-fill dam and construction method

The invention provides a layered filling structure of a rockfill material transition area of a face rock-fill dam and a construction method. The transition area structural form of primary rockfill area and secondary rockfill area filler layered alternate filling is arranged between an upstream primary rockfill area and a downstream secondary rockfill area, interbedding filling of soft and hard rockfill materials is adopted, transition of upstream and downstream rockfill materials is achieved, the problem of the large deformation modulus difference between the upstream high-quality primary rockfill area and the downstream poor-quality secondary rockfill area is solved, and the machining cost problem caused by independent design of transition area filler can be avoided; and meanwhile, the transition area filler source range is widened, technical guarantees are provided for application of a large quantity of completely and intensely weathered excavated materials to filling of the downstream secondary rockfill ar