PILE PERIPHERAL TUBULAR SPACE DRILLING CASING

PROBLEM TO BE SOLVED: To provide a drilling casing by which after a building is dismantled and removed, the periphery of a foundation pile remaining in the ground is drilled to be easily pulled out. SOLUTION: A drilling blade 1 is provided on the lower end of a casing main body 3, a drilling casing A has a spiral blade 2 for pushing up excavated earth on the outer peripheral surface of the casing main body 3, a discharged earth passing hole 4 is provided in the lower part of the casing main body 3, and the inside of the passing hole 4 is provided with a plow plate B adapted to open forward and close backward, seen from the rotating direction 5 of the drilling casing. When the drilling casing A is rotated, the plow plate removes earth in the periphery of the pile to be tubular shape through the passing hole 4.