High-low span stepped cavity structure in mountain building and construction method

The invention provides a stepped cavity structure at high and low spans in a mountain building and a construction method, and belongs to the technical field of building construction, the stepped cavity structure comprises a plurality of stepped cavity structure plates, a plurality of support columns, a plurality of top plate support changing beams, a plurality of anchor cables, a plurality of engineering columns, a road surface and a support monitoring assembly; the multiple stepped cavity structure plates are designed in a stepped mode, the reinforced concrete breast boards are arranged on one sides of the multiple supporting columns, the top plate support changing beams are arranged on one sides of the steel screen and the stepped cavity structure plates, and the top plate support changing beams are arranged in an inclined mode. The problems that in an existing construction technology, a support changing beam waterproof joint between a basement and a support structure cannot be treated and closed, the overa