Adjustable multiple coil extruding and expanding drilling tool

The invention relates to an adjustable multiple coil extruding and expanding drilling tool, comprising a hollow connecting rod, the lower part of the lateral wall of the connecting rod is provided with a helical blade, the bottom end of the connecting rod is provided with a drill, the connecting rod is coaxially connected with a plurality of helical extruding expanding bodies, the helical extruding expanding body is arranged between the helical blades, the margin of the cross section of each helical extruding expanding body is helical line, maximum outer diameter and minimum outer diameter ofeach helical extruding expanding body are respectively constant or increased from bottom to top, and the maximum outer diameter of each helical extruding expanding body is equal to or less than the outer diameter of the helical blade. The invention aims at providing an adjustable multiple coil extruding and expanding drilling tool which can penetrate thick hard clay or dense sand soil layer, avoid collapse when drilling into finished hole in high ground eater level and high hydrodynamic pressure stratum and can implement complete extruding soil or partial extruding soil type cast-in-place pile through multiple stage extruding and expanding at different depths by freely adjusting the position of multi-stage extruding expanding body according to longitudinal distribution of stratum.