Superimposed underground diaphragm wall structure

The utility model discloses a superimposed underground diaphragm wall structure. The underground diaphragm wall comprises a plurality of unit prefabricated diaphragm walls. Each unit prefabricated continuous wall comprises a post-cast concrete inner core and a prefabricated wall outer frame, each prefabricated wall outer frame comprises a superposed part outer wall plate, a superposed part inner wall plate, two vertical mud blocking side wall plates and a rectangular horizontal lower sealing bottom, and the two vertical mud blocking side wall plates are symmetrically arranged on a set of shortedges of the rectangular horizontal lower sealing bottom. And a groove is formed by the superposed part outer wall plate, the superposed part inner wall plate and the vertical mud blocking side wallplates arranged on the two sides. And the superposed prefabricated part is integrally manufactured in a prefabricated part factory processing form, so that the construction space and the early-stage preparation time of constru