Cutting drill bit for double-layer foundation rotary-expanding circular truncated cone pile construction

A cutting drill bit for double-layer foundation rotary expansion circular truncated cone pile construction comprises an outer sleeve, a hydraulic cylinder, a sliding shaft, a cutting blade, a hydraulic driving rod and a fixed shaft. First long-strip-shaped holes are formed in the left side and the right side of the outer sleeve. Second strip-shaped holes are formed in the upper parts of the frontside surface and the rear side surface of the outer sleeve; connecting holes are formed in the lower parts of the front and rear side surfaces of the outer sleeve; the hydraulic cylinder is mounted inthe outer sleeve and is close to the upper end; connecting rods are arranged at the bottoms of the hydraulic cylinders; the sliding shaft is longitudinally connected to the bottom of the connecting rod; the front and rear ends of the sliding shaft are respectively inserted into the second strip-shaped holes; the two cutting blades are hinged to the sliding shaft; the front and rear ends of the fixed shaft are inserted int