Rear implantation pile of expanded-base pier pit underpinning

The utility model relates to a rear implantation pile of expanded-base pier pit underpinning. The rear implantation pile of the expanded-base pier pit underpinning comprises a pile body part and an expanding head part, and the lower portion of the expanding head part is of a pan-bottom-shaped structure. The expanding head part is provided with anchor rods for supporting, and the anchor rods are of a radial structure. The ratio of the diameter D of the expanding head and the diameter d of the pile body is 2 to 2.9, the height h of the expanding head is 1.2m to 2m, and the height of the pan-bottom-shaped structure is 150mm to 200mm. The ratio of the width b of the expanding head and the height h of the expanding head is 1/3 to 1/2. The anchor rods are of a steel reinforcement cage structure, plain cement paste is poured, and the pile body is of a reinforced concrete structure. According to the rear implantation pile of the expanded-base pier pit underpinning, the sharing ratio of the original building foundatio