Root-like expandable foundation pile

A root-like expandable foundation pile, comprising:

• a movable drill, comprising:
• a control rod, having a guide bar parallelly formed thereon;
• and
• a conical drill bit, fixed on the end of the control rod, moving soil from a tip end to a tail end when being pushed and rotated in a first direction by the control rod;
• a foundation body, comprising:
• a bottom portion, having a circular cross-sectional shape;
• and
• a top portion, having a plurality of first upright sides and a regular polygon cross-sectional shape, wherein each first upright side has a first knuckle formed on a top side thereof, a first through hole is formed through the bottom portion and the top portion in the center of the foundation body, and the control rod is inserted in the first through hole, capable of moving along and out of the first through hole and being rotated synchronously with the foundation body;
• a plurality of foundation blade, each having two second knuckles on a swivel end and a warped portion protruding outward at an expanding end, being rotatably connected to the top portion by running a knuckle pin through the second knuckles and one of the first knuckles, being close to one corresponding first upright side by soil pressure exerted on an external side of the warped portion when the foundation body rotates in the first direction, and being rotated to expand from the corresponding first upright side by soil pressure exerted on an internal side of the warped portion when the foundation body rotates in a second direction opposite to the first direction;
• and
• a foundation cap, fixed on the top portion, having an outward appearance of a hollow cylinder with a plurality of connecting columns, each connected to the top portion where central lines of adjacent two knuckle pins are intersected.