Rotary excavating end bearing pile foundation in backfill soil and construction method

The invention relates to a rotary excavating end bearing pile foundation in backfill soil, which comprises a reinforcement cage, a plurality of support frames connected to the outer part of the reinforcement cage, and isolation pieces connected to the support frames and wrapping the reinforcement cage in the length direction of the reinforcement cage, the supporting frame comprises two first arc-shaped rods, four connecting rods, four connecting columns and two second arc-shaped rods. The two ends of the four connecting rods and the two ends of the four connecting columns are fixedly connected to the ends of the two first arc-shaped rods and the ends of the two second arc-shaped rods respectively. The supporting frame further comprises a nut and a screw, the nut is fixedly connected to the side close to the second arc-shaped rod, the screw is used in cooperation with the nut, and the isolation piece is connected to the supporting frame through the screw. The method has the effects that the friction resistance