The invention discloses a double-casing-
pipe double-drive full-rotation type
pile forming device. A double-casing-
pipe double-drive full-rotation drilling
machine, an upper clamp sheet, a lower clampsheet, an outer casing
pipe, an inner casing pipe and a
steel bar cage are included. The lower clamp sheet and the outer casing pipe are connected together, the outer casing pipe can be downwards pressed to penetrate through a refilling layer through forward rotation, and the outer casing pipe can be pulled out of the refilling layer through reverse rotation. The upper clamp sheet and the inner casing pipe are connected together, the inner casing pipe can be downwards pressed to penetrate through strong weathered rock and a
karst cave to enter a bearing stratum moderately-weathered limestone layer through forward rotation, and the inner casing pipe can be pulled out through reverse rotation. The
steel bar cage is arranged at the middle positions of the outer casing pipe and the inner casing pipe, a concrete guide pipe is arranged at the middle position of the
steel bar cage and can be lowered and hoisted along the center position of the steel bar cage, and a funnel is fixedly connectedto the upper end of the concrete guide pipe. By means of the double-casing-pipe double-drive full-rotation type
pile forming device, the ultra-long
pile construction depth can be achieved, the hole forming efficiency can be greatly improved, the hole forming depth can reach 120 m, and the problems that in deep refilling layer
karst development areas and other complex stratums, the pile length islimited, and the pile forming efficiency is too low are solved.