Composite foundation for reinforcing thick sand soil layer by using node piles

The invention relates to a composite foundation for reinforcing a thick sand soil layer by using node piles. The composite foundation is characterized by comprising a thick sand soil layer (1), node piles (2) and node pre-forming devices (7), wherein the node piles (2) adopt concrete structures and are inserted into the thick sand soil layer (1); each node pile (2) consists of a pile node (4) and a pile column (3); each node pre-forming device (7) consists of an elongating pipe (6) and a water spray nozzle (5); the node pre-forming devices (7) are positioned inside the node piles (2). Through the pile nodes of the node piles, the contact areas of the pile bodies and the thick sand soil layer can be enlarged; transverse ellipsoids of the pile nodes can effectively prevent a pile body from sinking, so that the area for a single pile body to reinforce soil is enlarged, and thus the distribution density of pile bodies can be reduced, the number of the pile bodies can be reduced, the cost is saved and the construction period is shortened.