Bottom expander of underground diaphragm wall

The utility model discloses a bottom expander of an underground diaphragm wall. The bottom expander comprises a hydraulic telescopic rod and an expansion plate, the two pairs of expansion plates are arranged in a left-right mirror image mode, the two pairs of expansion plates are distributed in a splayed shape, the opposite side ends of the expansion plates are hinged together, and the opposite sides of the expansion plates are hinged to the bottom of a cylinder body of the hydraulic telescopic rod and the end of a telescopic shaft of the hydraulic telescopic rod respectively. Compared with the prior art, the bottom expander for the underground diaphragm wall has the advantages that the bottom of the underground diaphragm wall can be expanded, and the contact area between the bottom of the underground diaphragm wall and a bearing stratum is increased, so that the bearing capacity of the underground diaphragm wall is greatly increased, the insertion depth of the underground diaphragm wall is reduced, and waste