Expansion pile and construction method thereof

The invention provides an expansion pile and a construction method thereof.The expansion pile comprises a first elastic restraining piece and an expansion column, a first column cavity is formed in the first elastic restraining piece, and water permeable holes communicating with the first column cavity are formed in the peripheral wall of the first elastic restraining piece; the expansion column is located in the first column cavity and extends in the axial direction of the first column cavity, the expansion pile further comprises a supporting piece, the supporting piece is located in the first column cavity and is adjacent to the inner circumferential wall of the first elastic restraining piece, and the supporting piece spirally extends in the axial direction of the first column cavity and is wound around the periphery of the expansion column; in the radial direction of the first column cavity, the area of the cross section of the expansion column is between 1/2 and 2/3 of the area of the cross section of th