Foundation pit structure and foundation pit construction method

The invention discloses a foundation pit structure and a foundation pit construction method, and relates to the technical field of foundation pit supporting construction. The device comprises mounting frames which are symmetrically arranged, sliding rails are symmetrically arranged at one ends of the mounting frames, ejection sliding blocks are slidably connected into the sliding rails, insertion holes are formed in one ends of the ejection sliding blocks, mounting rods are inserted into the insertion holes, and a plurality of protection plates are evenly arranged between every two adjacent mounting rods; a driving assembly is mounted at one end of the mounting frame, and a positioning assembly is mounted in the sliding rail. Through cooperative use of the driving assembly and the positioning assembly, the four mounting rods can be conveniently mounted at the four corners in the foundation pit correspondingly, meanwhile, the multiple protection plates are driven to be attached to the inner wall of the foundat