Combined type protective structure for adding steel pipe piles to slope retaining walls and construction method thereof

The invention discloses a combined type protective structure for adding steel pipe piles to slope retaining walls and a construction method thereof. The combined type protective structure comprises the steel pipe piles, retaining pile caps and retaining walls, wherein the steel pipe piles and the retaining pile caps are sequentially arranged from bottom to top in the direction of a to-be-supportedslope; one ends of the steel pipe piles are pre-buried into an underground soil bearing stratum, the other ends of the steel pipe piles are connected to the upper portions of the retaining pile caps,the multiple retaining walls are cast in situ at the tops of the retaining pile caps, and the multiple retaining walls are spliced into a whole and closely next to the surface of the to-be-supportedslope; filler is poured or filled into the steel pipe piles; and the outer walls of the upper ends of the steel pipe piles are annularly provided with a plurality of reinforcing supporting pieces. Thecombined type protective st