Method for constructing gravel pile composite foundation through soil borrowing and hole forming as well as high pressure jet grouting

The invention discloses a method for constructing a gravel pile composite foundation through soil borrowing and hole forming as well as high pressure jet grouting. The method comprises the following steps: through a long screw, borrowing soil to form a hole on a site to be constructed; after the hole is formed, placing gravels into the hole and tamping the gravels; placing a nozzle in the hole through a dynamic sounding guiding hole; carrying out high pressure jet grouting on the hole until slurry comes out from the top of the hole; manually eliminating a low-strength pile head; and laying a gravel bedding cushion on the pile to form the composite foundation with high bearing force. The construction method disclosed by the invention has the advantages as follows: as the soil is borrowed through the long screw to form the hole, the main structure of an original formation is not disturbed; through replacing the original soft and weak soil layer with the gravels, the bearing force is enhanced; as the gravels are