Method suitable for underground storey adding of frame-structure independent foundation building

The invention discloses a method suitable for underground storey adding of a frame-structure independent foundation building. The method solves the problem that basement storey adding in the prior art is severe in waste, and has the beneficial effects that waste of dismounting of pressed piles is reduced, and a new though is provided for underground storey adding of an existing building. The method includes the specific steps that earthwork above and around an independent foundation of the frame-structure building is excavated, and the independent foundation is exposed; a reaction frame and a jack are arranged on the top face of the independent foundation, and a precast pile is planted into the independent foundation through the reaction frame; the precast piles under all frame columns are connected in a pulling mode through rigid connecting parts to form a joint stress body; and a basement structure is constructed with the precast piles used as supporting columns of the basement structure.